21949956 has 36 divisors (see below), whose sum is σ = 63411712. Its totient is φ = 6271344.

The previous prime is 21949951. The next prime is 21949969. The reversal of 21949956 is 65994912.

It is a tau number, because it is divible by the number of its divisors (36).

It is not an unprimeable number, because it can be changed into a prime (21949951) 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, 43300 + ... + 43803.

Almost surely, 2^21949956 is an apocalyptic number.

It is an amenable number.

21949956 is an abundant number, since it is smaller than the sum of its proper divisors (41461756).

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

21949956 is a wasteful number, since it uses less digits than its factorization.

21949956 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87120 (or 87115 counting only the distinct ones).

The product of its digits is 174960, while the sum is 45.

The square root of 21949956 is about 4685.0780142918. The cubic root of 21949956 is about 279.9913092541.

The spelling of 21949956 in words is "twenty-one million, nine hundred forty-nine thousand, nine hundred fifty-six".