21631460 has 36 divisors (see below), whose sum is σ = 46272828. Its totient is φ = 8493888.

The previous prime is 21631447. The next prime is 21631469. The reversal of 21631460 is 6413612.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 7054336 + 14577124 = 2656^2 + 3818^2 .

It is not an unprimeable number, because it can be changed into a prime (21631469) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 137702 + ... + 137858.

Almost surely, 2^21631460 is an apocalyptic number.

21631460 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21631460 is an abundant number, since it is smaller than the sum of its proper divisors (24641368).

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

21631460 is a wasteful number, since it uses less digits than its factorization.

21631460 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 332 (or 247 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 21631460 is about 4650.9633410725. The cubic root of 21631460 is about 278.6304721909.

The spelling of 21631460 in words is "twenty-one million, six hundred thirty-one thousand, four hundred sixty".