21293172 has 24 divisors (see below), whose sum is σ = 55204800. Its totient is φ = 7097688.

The previous prime is 21293141. The next prime is 21293191. The reversal of 21293172 is 27139212.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 98472 + ... + 98687.

It is an arithmetic number, because the mean of its divisors is an integer number (2300200).

Almost surely, 2^21293172 is an apocalyptic number.

It is an amenable number.

21293172 is an abundant number, since it is smaller than the sum of its proper divisors (33911628).

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

21293172 is a wasteful number, since it uses less digits than its factorization.

21293172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 197172 (or 197164 counting only the distinct ones).

The product of its digits is 1512, while the sum is 27.

The square root of 21293172 is about 4614.4525135708. The cubic root of 21293172 is about 277.1703609546.

The spelling of 21293172 in words is "twenty-one million, two hundred ninety-three thousand, one hundred seventy-two".