21936788 has 12 divisors (see below), whose sum is σ = 38433780. Its totient is φ = 10955712.

The previous prime is 21936787. The next prime is 21936791. The reversal of 21936788 is 88763912.

It can be written as a sum of positive squares in 2 ways, for example, as 9560464 + 12376324 = 3092^2 + 3518^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21936781) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 1478 + ... + 6786.

It is an arithmetic number, because the mean of its divisors is an integer number (3202815).

Almost surely, 2^21936788 is an apocalyptic number.

It is an amenable number.

21936788 is a deficient number, since it is larger than the sum of its proper divisors (16496992).

21936788 is a wasteful number, since it uses less digits than its factorization.

21936788 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6346 (or 6344 counting only the distinct ones).

The product of its digits is 145152, while the sum is 44.

The square root of 21936788 is about 4683.6724906851. The cubic root of 21936788 is about 279.9353081839.

The spelling of 21936788 in words is "twenty-one million, nine hundred thirty-six thousand, seven hundred eighty-eight".