21261536 has 24 divisors (see below), whose sum is σ = 43210944. Its totient is φ = 10287360.

The previous prime is 21261517. The next prime is 21261563. The reversal of 21261536 is 63516212.

It is a congruent number.

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, 9725 + ... + 11708.

It is an arithmetic number, because the mean of its divisors is an integer number (1800456).

Almost surely, 2^21261536 is an apocalyptic number.

It is an amenable number.

21261536 is an abundant number, since it is smaller than the sum of its proper divisors (21949408).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21261536 is a wasteful number, since it uses less digits than its factorization.

21261536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21474 (or 21466 counting only the distinct ones).

The product of its digits is 2160, while the sum is 26.

The square root of 21261536 is about 4611.0233137559. The cubic root of 21261536 is about 277.0330257295.

Adding to 21261536 its reverse (63516212), we get a palindrome (84777748).

The spelling of 21261536 in words is "twenty-one million, two hundred sixty-one thousand, five hundred thirty-six".