21371524 has 12 divisors (see below), whose sum is σ = 38606848. Its totient is φ = 10341000.

The previous prime is 21371509. The next prime is 21371551. The reversal of 21371524 is 42517312.

It is a happy number.

It is a hoax number, since the sum of its digits (25) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 86052 + ... + 86299.

Almost surely, 2^21371524 is an apocalyptic number.

It is an amenable number.

21371524 is a deficient number, since it is larger than the sum of its proper divisors (17235324).

21371524 is a wasteful number, since it uses less digits than its factorization.

21371524 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172386 (or 172384 counting only the distinct ones).

The product of its digits is 1680, while the sum is 25.

The square root of 21371524 is about 4622.9345658359. The cubic root of 21371524 is about 277.5099106381.

Adding to 21371524 its reverse (42517312), we get a palindrome (63888836).

The spelling of 21371524 in words is "twenty-one million, three hundred seventy-one thousand, five hundred twenty-four".