21587992 has 8 divisors (see below), whose sum is σ = 40477500. Its totient is φ = 10793992.

The previous prime is 21587987. The next prime is 21588001. The reversal of 21587992 is 29978512.

It is a tau number, because it is divible by the number of its divisors (8).

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, 1349242 + ... + 1349257.

Almost surely, 2^21587992 is an apocalyptic number.

It is an amenable number.

21587992 is a deficient number, since it is larger than the sum of its proper divisors (18889508).

21587992 is a wasteful number, since it uses less digits than its factorization.

21587992 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2698505 (or 2698501 counting only the distinct ones).

The product of its digits is 90720, while the sum is 43.

The square root of 21587992 is about 4646.2879807433. The cubic root of 21587992 is about 278.4437128591.

The spelling of 21587992 in words is "twenty-one million, five hundred eighty-seven thousand, nine hundred ninety-two".