21517136 has 10 divisors (see below), whose sum is σ = 41689482. Its totient is φ = 10758560.

The previous prime is 21517127. The next prime is 21517163. The reversal of 21517136 is 63171512.

It can be written as a sum of positive squares in only one way, i.e., 13987600 + 7529536 = 3740^2 + 2744^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 672395 + ... + 672426.

Almost surely, 2^21517136 is an apocalyptic number.

It is an amenable number.

21517136 is a deficient number, since it is larger than the sum of its proper divisors (20172346).

21517136 is a wasteful number, since it uses less digits than its factorization.

21517136 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1344829 (or 1344823 counting only the distinct ones).

The product of its digits is 1260, while the sum is 26.

The square root of 21517136 is about 4638.6567021068. The cubic root of 21517136 is about 278.1387434357.

Adding to 21517136 its reverse (63171512), we get a palindrome (84688648).

The spelling of 21517136 in words is "twenty-one million, five hundred seventeen thousand, one hundred thirty-six".