21712528 has 20 divisors (see below), whose sum is σ = 42152188. Its totient is φ = 10834560.

The previous prime is 21712513. The next prime is 21712541. The reversal of 21712528 is 82521712.

It can be written as a sum of positive squares in 2 ways, for example, as 14379264 + 7333264 = 3792^2 + 2708^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21712496 and 21712505.

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 in 3 ways as a sum of consecutive naturals, for example, 9550 + ... + 11602.

Almost surely, 2^21712528 is an apocalyptic number.

It is an amenable number.

21712528 is a deficient number, since it is larger than the sum of its proper divisors (20439660).

21712528 is a wasteful number, since it uses less digits than its factorization.

21712528 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2722 (or 2716 counting only the distinct ones).

The product of its digits is 2240, while the sum is 28.

The square root of 21712528 is about 4659.6703746081. The cubic root of 21712528 is about 278.9781117877.

The spelling of 21712528 in words is "twenty-one million, seven hundred twelve thousand, five hundred twenty-eight".