20939631 has 16 divisors (see below), whose sum is σ = 30067200. Its totient is φ = 12914048.

The previous prime is 20939627. The next prime is 20939641. The reversal of 20939631 is 13693902.

It is a cyclic number.

It is not a de Polignac number, because 20939631 - 2² = 20939627 is a prime.

It is a super-2 number, since 2×20939631² = 876936292832322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20939592 and 20939601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20939621) 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, 471 + ... + 6488.

It is an arithmetic number, because the mean of its divisors is an integer number (1879200).

Almost surely, 2^20939631 is an apocalyptic number.

20939631 is a deficient number, since it is larger than the sum of its proper divisors (9127569).

20939631 is a wasteful number, since it uses less digits than its factorization.

20939631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7038.

The product of its (nonzero) digits is 8748, while the sum is 33.

The square root of 20939631 is about 4575.9841564411. The cubic root of 20939631 is about 275.6277932780.

The spelling of 20939631 in words is "twenty million, nine hundred thirty-nine thousand, six hundred thirty-one".