21537536 has 18 divisors (see below), whose sum is σ = 42991452. Its totient is φ = 10768640.

The previous prime is 21537497. The next prime is 21537541. The reversal of 21537536 is 63573512.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41810 + ... + 42321.

It is an arithmetic number, because the mean of its divisors is an integer number (2388414).

Almost surely, 2^21537536 is an apocalyptic number.

It is an amenable number.

21537536 is a deficient number, since it is larger than the sum of its proper divisors (21453916).

21537536 is an frugal number, since it uses more digits than its factorization.

21537536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84147 (or 84133 counting only the distinct ones).

The product of its digits is 18900, while the sum is 32.

The square root of 21537536 is about 4640.8550936223. The cubic root of 21537536 is about 278.2266150769.

The spelling of 21537536 in words is "twenty-one million, five hundred thirty-seven thousand, five hundred thirty-six".