40020 has 48 divisors (see below), whose sum is σ = 120960. Its totient is φ = 9856.

The previous prime is 40013. The next prime is 40031. The reversal of 40020 is 2004.

40020 = T₅₃ + T₅₄ + ... + T₇₂.

40020 is nontrivially palindromic in base 9 and base 11.

It is a Harshad number since it is a multiple of its sum of digits (6).

It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.

It is a junction number, because it is equal to n+sod(n) for n = 39990 and 40008.

It is a congruent number.

It is an unprimeable number.

40020 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1366 + ... + 1394.

It is an arithmetic number, because the mean of its divisors is an integer number (2520).

2⁴⁰⁰²⁰ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 40020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (60480).

40020 is an abundant number, since it is smaller than the sum of its proper divisors (80940).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

40020 is a wasteful number, since it uses less digits than its factorization.

40020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64 (or 62 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 6.

The square root of 40020 is about 200.0499937516. The cubic root of 40020 is about 34.2052179036.

Adding to 40020 its reverse (2004), we get a palindrome (42024).

It can be divided in two parts, 400 and 20, that multiplied together give a cube (8000 = 20³).

The spelling of 40020 in words is "forty thousand, twenty", and thus it is an iban number.