21995208 has 24 divisors (see below), whose sum is σ = 59570550. Its totient is φ = 7331712.

The previous prime is 21995203. The next prime is 21995209. The reversal of 21995208 is 80259912.

It can be written as a sum of positive squares in only one way, i.e., 14607684 + 7387524 = 3822^2 + 2718^2 .

It is a tau number, because it is divible by the number of its divisors (24).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (21995203) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 152673 + ... + 152816.

Almost surely, 2^21995208 is an apocalyptic number.

It is an amenable number.

21995208 is an abundant number, since it is smaller than the sum of its proper divisors (37575342).

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

21995208 is a wasteful number, since it uses less digits than its factorization.

21995208 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 305501 (or 305494 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 21995208 is about 4689.9049030871. The cubic root of 21995208 is about 280.1835870845.

The spelling of 21995208 in words is "twenty-one million, nine hundred ninety-five thousand, two hundred eight".