21169900800 has 540 divisors, whose sum is σ = 79269567916. Its totient is φ = 5573836800.

The previous prime is 21169900799. The next prime is 21169900813. The reversal of 21169900800 is 800996112.

It can be written as a sum of positive squares in 6 ways, for example, as 5330168064 + 15839732736 = 73008^2 + 125856^2 .

It is a tau number, because it is divible by the number of its divisors (540).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 50284590 + ... + 50285010.

Almost surely, 2^21169900800 is an apocalyptic number.

21169900800 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 21169900800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39634783958).

21169900800 is an abundant number, since it is smaller than the sum of its proper divisors (58099667116).

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

21169900800 is an equidigital number, since it uses as much as digits as its factorization.

21169900800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 556 (or 528 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 36.

The spelling of 21169900800 in words is "twenty-one billion, one hundred sixty-nine million, nine hundred thousand, eight hundred".