21587572 has 24 divisors (see below), whose sum is σ = 39916800. Its totient is φ = 10187136.

The previous prime is 21587551. The next prime is 21587611. The reversal of 21587572 is 27578512.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 36108 + ... + 36700.

It is an arithmetic number, because the mean of its divisors is an integer number (1663200).

Almost surely, 2^21587572 is an apocalyptic number.

It is an amenable number.

21587572 is a deficient number, since it is larger than the sum of its proper divisors (18329228).

21587572 is a wasteful number, since it uses less digits than its factorization.

21587572 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1095 (or 1093 counting only the distinct ones).

The product of its digits is 39200, while the sum is 37.

The square root of 21587572 is about 4646.2427831529. The cubic root of 21587572 is about 278.4419071157.

It can be divided in two parts, 2158 and 7572, that added together give a triangular number (9730 = T₁₃₉).

The spelling of 21587572 in words is "twenty-one million, five hundred eighty-seven thousand, five hundred seventy-two".