21990945600 has 504 divisors, whose sum is σ = 85296207360. Its totient is φ = 5341040640.

The previous prime is 21990945593. The next prime is 21990945703. The reversal of 21990945600 is 654909912.

21990945600 is a `hidden beast` number, since 2 + 199 + 0 + 9 + 456 + 0 + 0 = 666.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 14788057 + ... + 14789543.

Almost surely, 2^21990945600 is an apocalyptic number.

21990945600 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21990945600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42648103680).

21990945600 is an abundant number, since it is smaller than the sum of its proper divisors (63305261760).

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

21990945600 is a wasteful number, since it uses less digits than its factorization.

21990945600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1607 (or 1589 counting only the distinct ones).

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

The spelling of 21990945600 in words is "twenty-one billion, nine hundred ninety million, nine hundred forty-five thousand, six hundred".