40640 has 28 divisors (see below), whose sum is σ = 97536. Its totient is φ = 16128.

The previous prime is 40639. The next prime is 40693. The reversal of 40640 is 4604.

It is a happy number.

40640 is an admirable number.

It is an unprimeable 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 3 ways as a sum of consecutive naturals, for example, 257 + ... + 383.

2⁴⁰⁶⁴⁰ is an apocalyptic number.

40640 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 40640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48768).

40640 is an abundant number, since it is smaller than the sum of its proper divisors (56896).

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

40640 is a wasteful number, since it uses less digits than its factorization.

40640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144 (or 134 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 14.

The square root of 40640 is about 201.5936506937. The cubic root of 40640 is about 34.3809521374.

It can be divided in two parts, 40 and 640, that multiplied together give a square (25600 = 160²).

The spelling of 40640 in words is "forty thousand, six hundred forty".