21885912 has 48 divisors (see below), whose sum is σ = 59613840. Its totient is φ = 7253568.

The previous prime is 21885893. The next prime is 21885917. The reversal of 21885912 is 21958812.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21885917) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13413 + ... + 14955.

It is an arithmetic number, because the mean of its divisors is an integer number (1241955).

Almost surely, 2^21885912 is an apocalyptic number.

It is an amenable number.

21885912 is an abundant number, since it is smaller than the sum of its proper divisors (37727928).

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

21885912 is a wasteful number, since it uses less digits than its factorization.

21885912 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1752 (or 1745 counting only the distinct ones).

The product of its digits is 11520, while the sum is 36.

The square root of 21885912 is about 4678.2381298946. The cubic root of 21885912 is about 279.7187311566.

Subtracting 21885912 from its reverse (21958812), we obtain a square (72900 = 270²).

It can be divided in two parts, 2188 and 5912, that added together give a square (8100 = 90²).

The spelling of 21885912 in words is "twenty-one million, eight hundred eighty-five thousand, nine hundred twelve".