21633674400 has 720 divisors, whose sum is σ = 86560506648. Its totient is φ = 5225472000.

The previous prime is 21633674399. The next prime is 21633674407. The reversal of 21633674400 is 447633612.

It is a happy number.

21633674400 is a `hidden beast` number, since 216 + 3 + 36 + 7 + 4 + 400 = 666.

It can be written as a sum of positive squares in 12 ways, for example, as 6993642384 + 14640032016 = 83628^2 + 120996^2 .

It is a tau number, because it is divible by the number of its divisors (720).

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 (21633674407) by changing a digit.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 51386190 + ... + 51386610.

Almost surely, 2^21633674400 is an apocalyptic number.

21633674400 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 21633674400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43280253324).

21633674400 is an abundant number, since it is smaller than the sum of its proper divisors (64926832248).

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

21633674400 is a wasteful number, since it uses less digits than its factorization.

21633674400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 527 (or 505 counting only the distinct ones).

The product of its (nonzero) digits is 72576, while the sum is 36.

The spelling of 21633674400 in words is "twenty-one billion, six hundred thirty-three million, six hundred seventy-four thousand, four hundred".