20909688 has 32 divisors (see below), whose sum is σ = 52760400. Its totient is φ = 6905088.

The previous prime is 20909657. The next prime is 20909701. The reversal of 20909688 is 88690902.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1381 + ... + 6612.

Almost surely, 2^20909688 is an apocalyptic number.

It is an amenable number.

20909688 is an abundant number, since it is smaller than the sum of its proper divisors (31850712).

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

20909688 is a wasteful number, since it uses less digits than its factorization.

20909688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8111 (or 8107 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 42.

The square root of 20909688 is about 4572.7112307689. The cubic root of 20909688 is about 275.4963509738.

The spelling of 20909688 in words is "twenty million, nine hundred nine thousand, six hundred eighty-eight".