21099272 has 32 divisors (see below), whose sum is σ = 42009600. Its totient is φ = 9906624.

The previous prime is 21099187. The next prime is 21099277. The reversal of 21099272 is 27299012.

It is not an unprimeable number, because it can be changed into a prime (21099277) 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, 18758 + ... + 19850.

It is an arithmetic number, because the mean of its divisors is an integer number (1312800).

Almost surely, 2^21099272 is an apocalyptic number.

It is an amenable number.

21099272 is a deficient number, since it is larger than the sum of its proper divisors (20910328).

21099272 is a wasteful number, since it uses less digits than its factorization.

21099272 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1245 (or 1241 counting only the distinct ones).

The product of its (nonzero) digits is 4536, while the sum is 32.

The square root of 21099272 is about 4593.3943875962. The cubic root of 21099272 is about 276.3264707797.

The spelling of 21099272 in words is "twenty-one million, ninety-nine thousand, two hundred seventy-two".