21913536 has 56 divisors (see below), whose sum is σ = 61041280. Its totient is φ = 6918912.

The previous prime is 21913523. The next prime is 21913543. The reversal of 21913536 is 63531912.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 645 + ... + 6651.

Almost surely, 2^21913536 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21913536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30520640).

21913536 is an abundant number, since it is smaller than the sum of its proper divisors (39127744).

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

21913536 is a wasteful number, since it uses less digits than its factorization.

21913536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6041 (or 6031 counting only the distinct ones).

The product of its digits is 4860, while the sum is 30.

The square root of 21913536 is about 4681.1895924006. The cubic root of 21913536 is about 279.8363669759.

The spelling of 21913536 in words is "twenty-one million, nine hundred thirteen thousand, five hundred thirty-six".