21237172 has 12 divisors (see below), whose sum is σ = 40543776. Its totient is φ = 9653240.

The previous prime is 21237157. The next prime is 21237173. The reversal of 21237172 is 27173212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21237173) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 241288 + ... + 241375.

It is an arithmetic number, because the mean of its divisors is an integer number (3378648).

Almost surely, 2^21237172 is an apocalyptic number.

21237172 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21237172 is a deficient number, since it is larger than the sum of its proper divisors (19306604).

21237172 is a wasteful number, since it uses less digits than its factorization.

21237172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 482678 (or 482676 counting only the distinct ones).

The product of its digits is 1176, while the sum is 25.

The square root of 21237172 is about 4608.3806266410. The cubic root of 21237172 is about 276.9271661394.

The spelling of 21237172 in words is "twenty-one million, two hundred thirty-seven thousand, one hundred seventy-two".