21990729600 has 432 divisors, whose sum is σ = 91284916320. Its totient is φ = 5026129920.

The previous prime is 21990729557. The next prime is 21990729601. The reversal of 21990729600 is 692709912.

21990729600 is a `hidden beast` number, since 2 + 19 + 9 + 0 + 7 + 29 + 600 = 666.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21990729601) by changing a digit.

It is a polite number, since it can be written in 53 ways as a sum of consecutive naturals, for example, 1403409 + ... + 1418991.

Almost surely, 2^21990729600 is an apocalyptic number.

21990729600 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 21990729600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45642458160).

21990729600 is an abundant number, since it is smaller than the sum of its proper divisors (69294186720).

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

21990729600 is a wasteful number, since it uses less digits than its factorization.

21990729600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15627 (or 15600 counting only the distinct ones).

The product of its (nonzero) digits is 122472, while the sum is 45.

The spelling of 21990729600 in words is "twenty-one billion, nine hundred ninety million, seven hundred twenty-nine thousand, six hundred".