21857272 has 16 divisors (see below), whose sum is σ = 41043240. Its totient is φ = 10912416.

The previous prime is 21857233. The next prime is 21857273. The reversal of 21857272 is 27275812.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21857273) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5223 + ... + 8425.

Almost surely, 2^21857272 is an apocalyptic number.

It is an amenable number.

21857272 is a deficient number, since it is larger than the sum of its proper divisors (19185968).

21857272 is a wasteful number, since it uses less digits than its factorization.

21857272 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4062 (or 4058 counting only the distinct ones).

The product of its digits is 15680, while the sum is 34.

The square root of 21857272 is about 4675.1761464142. The cubic root of 21857272 is about 279.5966641777.

The spelling of 21857272 in words is "twenty-one million, eight hundred fifty-seven thousand, two hundred seventy-two".