21975124 has 6 divisors (see below), whose sum is σ = 38456474. Its totient is φ = 10987560.

The previous prime is 21975113. The next prime is 21975131. The reversal of 21975124 is 42157912.

21975124 is nontrivially palindromic in base 3.

It can be written as a sum of positive squares in only one way, i.e., 21790224 + 184900 = 4668^2 + 430^2 .

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, 2746887 + ... + 2746894.

Almost surely, 2^21975124 is an apocalyptic number.

It is an amenable number.

21975124 is a deficient number, since it is larger than the sum of its proper divisors (16481350).

21975124 is a wasteful number, since it uses less digits than its factorization.

21975124 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5493785 (or 5493783 counting only the distinct ones).

The product of its digits is 5040, while the sum is 31.

The square root of 21975124 is about 4687.7632192763. The cubic root of 21975124 is about 280.0982818249.

The spelling of 21975124 in words is "twenty-one million, nine hundred seventy-five thousand, one hundred twenty-four".