20631 has 12 divisors (see below), whose sum is σ = 30968. Its totient is φ = 12144.

The previous prime is 20627. The next prime is 20639. The reversal of 20631 is 13602.

It is not a de Polignac number, because 20631 - 2² = 20627 is a prime.

It is a super-2 number, since 2×20631² = 851276322, which contains 22 as substring.

It is a hoax number, since the sum of its digits (12) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is a plaindrome in base 11.

It is a nialpdrome in base 12 and base 13.

It is a zygodrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20639) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 886 + ... + 908.

2²⁰⁶³¹ is an apocalyptic number.

20631 is a deficient number, since it is larger than the sum of its proper divisors (10337).

20631 is a wasteful number, since it uses less digits than its factorization.

20631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62 (or 39 counting only the distinct ones).

The product of its (nonzero) digits is 36, while the sum is 12.

The square root of 20631 is about 143.6349539632. The cubic root of 20631 is about 27.4266918045.

The spelling of 20631 in words is "twenty thousand, six hundred thirty-one".