20656638 has 12 divisors (see below), whose sum is σ = 44756088. Its totient is φ = 6885540.

The previous prime is 20656631. The next prime is 20656639. The reversal of 20656638 is 83665602.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20656631) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 573778 + ... + 573813.

It is an arithmetic number, because the mean of its divisors is an integer number (3729674).

Almost surely, 2^20656638 is an apocalyptic number.

20656638 is an abundant number, since it is smaller than the sum of its proper divisors (24099450).

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

20656638 is a wasteful number, since it uses less digits than its factorization.

20656638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1147599 (or 1147596 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The square root of 20656638 is about 4544.9574255432. The cubic root of 20656638 is about 274.3804808794.

The spelling of 20656638 in words is "twenty million, six hundred fifty-six thousand, six hundred thirty-eight".