21731460 has 24 divisors (see below), whose sum is σ = 60848256. Its totient is φ = 5795040.

The previous prime is 21731453. The next prime is 21731473. The reversal of 21731460 is 6413712.

It is a self number, because there is not a number n which added to its sum of digits gives 21731460.

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, 181036 + ... + 181155.

It is an arithmetic number, because the mean of its divisors is an integer number (2535344).

Almost surely, 2^21731460 is an apocalyptic number.

21731460 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21731460 is an abundant number, since it is smaller than the sum of its proper divisors (39116796).

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

21731460 is a wasteful number, since it uses less digits than its factorization.

21731460 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 362203 (or 362201 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 24.

The square root of 21731460 is about 4661.7014061392. The cubic root of 21731460 is about 279.0591721979.

The spelling of 21731460 in words is "twenty-one million, seven hundred thirty-one thousand, four hundred sixty".