21271924 has 6 divisors (see below), whose sum is σ = 37225874. Its totient is φ = 10635960.

The previous prime is 21271903. The next prime is 21271931. The reversal of 21271924 is 42917212.

It can be written as a sum of positive squares in only one way, i.e., 13927824 + 7344100 = 3732^2 + 2710^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21271892 and 21271901.

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 as a sum of consecutive naturals, namely, 2658987 + ... + 2658994.

Almost surely, 2^21271924 is an apocalyptic number.

It is an amenable number.

21271924 is a deficient number, since it is larger than the sum of its proper divisors (15953950).

21271924 is a wasteful number, since it uses less digits than its factorization.

21271924 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5317985 (or 5317983 counting only the distinct ones).

The product of its digits is 2016, while the sum is 28.

The square root of 21271924 is about 4612.1496072873. The cubic root of 21271924 is about 277.0781361504.

The spelling of 21271924 in words is "twenty-one million, two hundred seventy-one thousand, nine hundred twenty-four".