21955808 has 24 divisors (see below), whose sum is σ = 49401072. Its totient is φ = 9409536.

The previous prime is 21955807. The next prime is 21955831. The reversal of 21955808 is 80855912.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21955807) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 48785 + ... + 49232.

It is an arithmetic number, because the mean of its divisors is an integer number (2058378).

Almost surely, 2^21955808 is an apocalyptic number.

21955808 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21955808 is an abundant number, since it is smaller than the sum of its proper divisors (27445264).

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

21955808 is an equidigital number, since it uses as much as digits as its factorization.

21955808 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98034 (or 98026 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 38.

The square root of 21955808 is about 4685.7025086960. The cubic root of 21955808 is about 280.0161895401.

The spelling of 21955808 in words is "twenty-one million, nine hundred fifty-five thousand, eight hundred eight".