20897772690 has 32 divisors (see below), whose sum is σ = 50174591040. Its totient is φ = 5570524224.

The previous prime is 20897772689. The next prime is 20897772697. The reversal of 20897772690 is 9627779802.

It is a super-2 number, since 2×20897772690² (a number of 21 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (57) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 20897772690.

It is not an unprimeable number, because it can be changed into a prime (20897772697) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 61009 + ... + 213348.

It is an arithmetic number, because the mean of its divisors is an integer number (1567955970).

Almost surely, 2^20897772690 is an apocalyptic number.

20897772690 is an abundant number, since it is smaller than the sum of its proper divisors (29276818350).

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

20897772690 is a wasteful number, since it uses less digits than its factorization.

20897772690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 276906.

The product of its (nonzero) digits is 5334336, while the sum is 57.

The spelling of 20897772690 in words is "twenty billion, eight hundred ninety-seven million, seven hundred seventy-two thousand, six hundred ninety".