9921621900 has 36 divisors (see below), whose sum is σ = 28706560232. Its totient is φ = 2645765760.

The previous prime is 9921621887. The next prime is 9921621937. The reversal of 9921621900 is 91261299.

It is a super-2 number, since 2×9921621900² (a number of 21 digits) contains 22 as substring.

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, 16535737 + ... + 16536336.

Almost surely, 2^9921621900 is an apocalyptic number.

It is an amenable number.

9921621900 is an abundant number, since it is smaller than the sum of its proper divisors (18784938332).

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

9921621900 is a wasteful number, since it uses less digits than its factorization.

9921621900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33072090 (or 33072083 counting only the distinct ones).

The product of its (nonzero) digits is 17496, while the sum is 39.

The square root of 9921621900 is about 99607.3385850661. The cubic root of 9921621900 is about 2148.7912368933.

The spelling of 9921621900 in words is "nine billion, nine hundred twenty-one million, six hundred twenty-one thousand, nine hundred".