21955208 has 48 divisors (see below), whose sum is σ = 46547340. Its totient is φ = 9694080.

The previous prime is 21955187. The next prime is 21955217. The reversal of 21955208 is 80255912.

It can be written as a sum of positive squares in 2 ways, for example, as 21548164 + 407044 = 4642^2 + 638^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 35510 + ... + 36122.

Almost surely, 2^21955208 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 21955208, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23273670).

21955208 is an abundant number, since it is smaller than the sum of its proper divisors (24592132).

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

21955208 is a wasteful number, since it uses less digits than its factorization.

21955208 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 678 (or 663 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 32.

The square root of 21955208 is about 4685.6384837074. The cubic root of 21955208 is about 280.0136387914.

The spelling of 21955208 in words is "twenty-one million, nine hundred fifty-five thousand, two hundred eight".