21955992 has 64 divisors (see below), whose sum is σ = 57425760. Its totient is φ = 6988800.

The previous prime is 21955981. The next prime is 21956009. The reversal of 21955992 is 29955912.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 51942 + ... + 52362.

Almost surely, 2^21955992 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 21955992, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28712880).

21955992 is an abundant number, since it is smaller than the sum of its proper divisors (35469768).

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

21955992 is a wasteful number, since it uses less digits than its factorization.

21955992 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 524 (or 520 counting only the distinct ones).

The product of its digits is 72900, while the sum is 42.

The square root of 21955992 is about 4685.7221428506. The cubic root of 21955992 is about 280.0169717604.

The spelling of 21955992 in words is "twenty-one million, nine hundred fifty-five thousand, nine hundred ninety-two".