21906888 has 32 divisors (see below), whose sum is σ = 55935360. Its totient is φ = 7146560.

The previous prime is 21906887. The next prime is 21906889. The reversal of 21906888 is 88860912.

It is an interprime number because it is at equal distance from previous prime (21906887) and next prime (21906889).

It is not an unprimeable number, because it can be changed into a prime (21906883) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8583 + ... + 10838.

It is an arithmetic number, because the mean of its divisors is an integer number (1747980).

Almost surely, 2^21906888 is an apocalyptic number.

It is an amenable number.

21906888 is an abundant number, since it is smaller than the sum of its proper divisors (34028472).

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

21906888 is a wasteful number, since it uses less digits than its factorization.

21906888 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19477 (or 19473 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 42.

The square root of 21906888 is about 4680.4794626192. The cubic root of 21906888 is about 279.8080657420.

The spelling of 21906888 in words is "twenty-one million, nine hundred six thousand, eight hundred eighty-eight".