20397120156 has 72 divisors (see below), whose sum is σ = 58948422624. Its totient is φ = 5825433600.

The previous prime is 20397120151. The next prime is 20397120167. The reversal of 20397120156 is 65102179302.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 20397120156.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20397120151) 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, 679056 + ... + 708456.

It is an arithmetic number, because the mean of its divisors is an integer number (818728092).

Almost surely, 2^20397120156 is an apocalyptic number.

It is an amenable number.

20397120156 is an abundant number, since it is smaller than the sum of its proper divisors (38551302468).

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

20397120156 is a wasteful number, since it uses less digits than its factorization.

20397120156 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32171 (or 32166 counting only the distinct ones).

The product of its (nonzero) digits is 22680, while the sum is 36.

Adding to 20397120156 its reverse (65102179302), we get a palindrome (85499299458).

The spelling of 20397120156 in words is "twenty billion, three hundred ninety-seven million, one hundred twenty thousand, one hundred fifty-six".