21731260 has 24 divisors (see below), whose sum is σ = 45969840. Its totient is φ = 8628864.

The previous prime is 21731257. The next prime is 21731263. The reversal of 21731260 is 6213712.

It is an interprime number because it is at equal distance from previous prime (21731257) and next prime (21731263).

It is a super-2 number, since 2×21731260² = 944495322375200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21731263) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1129 + ... + 6688.

It is an arithmetic number, because the mean of its divisors is an integer number (1915410).

Almost surely, 2^21731260 is an apocalyptic number.

21731260 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21731260 is an abundant number, since it is smaller than the sum of its proper divisors (24238580).

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

21731260 is a wasteful number, since it uses less digits than its factorization.

21731260 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7965 (or 7963 counting only the distinct ones).

The product of its (nonzero) digits is 504, while the sum is 22.

The square root of 21731260 is about 4661.6799546944. The cubic root of 21731260 is about 279.0583161117.

Adding to 21731260 its reverse (6213712), we get a palindrome (27944972).

The spelling of 21731260 in words is "twenty-one million, seven hundred thirty-one thousand, two hundred sixty".