20655657 has 24 divisors (see below), whose sum is σ = 33433920. Its totient is φ = 12178080.

The previous prime is 20655653. The next prime is 20655659. The reversal of 20655657 is 75655602.

It is not a de Polignac number, because 20655657 - 2² = 20655653 is a prime.

It is a super-2 number, since 2×20655657² = 853312332203298, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20655653) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 844 + ... + 6482.

It is an arithmetic number, because the mean of its divisors is an integer number (1393080).

Almost surely, 2^20655657 is an apocalyptic number.

It is an amenable number.

20655657 is a deficient number, since it is larger than the sum of its proper divisors (12778263).

20655657 is a wasteful number, since it uses less digits than its factorization.

20655657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5693 (or 5690 counting only the distinct ones).

The product of its (nonzero) digits is 63000, while the sum is 36.

The square root of 20655657 is about 4544.8495024588. The cubic root of 20655657 is about 274.3761372957.

Subtracting 20655657 from its reverse (75655602), we obtain a palindrome (54999945).

It can be divided in two parts, 20655 and 657, that added together give a palindrome (21312).

The spelling of 20655657 in words is "twenty million, six hundred fifty-five thousand, six hundred fifty-seven".