21956895 has 24 divisors (see below), whose sum is σ = 38443392. Its totient is φ = 11592000.

The previous prime is 21956887. The next prime is 21956941. The reversal of 21956895 is 59865912.

It is not a de Polignac number, because 21956895 - 2³ = 21956887 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 21956895.

It is a congruent number.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 2130 + ... + 6960.

It is an arithmetic number, because the mean of its divisors is an integer number (1601808).

Almost surely, 2^21956895 is an apocalyptic number.

21956895 is a deficient number, since it is larger than the sum of its proper divisors (16486497).

21956895 is a wasteful number, since it uses less digits than its factorization.

21956895 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4943 (or 4940 counting only the distinct ones).

The product of its digits is 194400, while the sum is 45.

The square root of 21956895 is about 4685.8184984056. The cubic root of 21956895 is about 280.0208105281.

The spelling of 21956895 in words is "twenty-one million, nine hundred fifty-six thousand, eight hundred ninety-five".