21031272 has 32 divisors (see below), whose sum is σ = 58420800. Its totient is φ = 7010352.

The previous prime is 21031253. The next prime is 21031277. The reversal of 21031272 is 27213012.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (21031277) 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, 48468 + ... + 48899.

It is an arithmetic number, because the mean of its divisors is an integer number (1825650).

Almost surely, 2^21031272 is an apocalyptic number.

It is an amenable number.

21031272 is an abundant number, since it is smaller than the sum of its proper divisors (37389528).

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

21031272 is a wasteful number, since it uses less digits than its factorization.

21031272 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97382 (or 97372 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 18.

The square root of 21031272 is about 4585.9864805732. The cubic root of 21031272 is about 276.0292974571.

Adding to 21031272 its reverse (27213012), we get a palindrome (48244284).

It can be divided in two parts, 2103 and 1272, that added together give a cube (3375 = 15³).

The spelling of 21031272 in words is "twenty-one million, thirty-one thousand, two hundred seventy-two".