20315540 has 72 divisors (see below), whose sum is σ = 50714496. Its totient is φ = 6696000.

The previous prime is 20315531. The next prime is 20315543. The reversal of 20315540 is 4551302.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20315543) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 134465 + ... + 134615.

It is an arithmetic number, because the mean of its divisors is an integer number (704368).

Almost surely, 2^20315540 is an apocalyptic number.

20315540 is a gapful number since it is divisible by the number (20) 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 20315540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25357248).

20315540 is an abundant number, since it is smaller than the sum of its proper divisors (30398956).

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

20315540 is a wasteful number, since it uses less digits than its factorization.

20315540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 229 (or 196 counting only the distinct ones).

The product of its (nonzero) digits is 600, while the sum is 20.

The square root of 20315540 is about 4507.2763394316. The cubic root of 20315540 is about 272.8618317144.

Adding to 20315540 its reverse (4551302), we get a palindrome (24866842).

The spelling of 20315540 in words is "twenty million, three hundred fifteen thousand, five hundred forty".