21025396800 has 420 divisors, whose sum is σ = 78767984196. Its totient is φ = 5499187200.

The previous prime is 21025396793. The next prime is 21025396813. The reversal of 21025396800 is 869352012.

It can be written as a sum of positive squares in 6 ways, for example, as 1353651264 + 19671745536 = 36792^2 + 140256^2 .

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 6867270 + ... + 6870330.

Almost surely, 2^21025396800 is an apocalyptic number.

21025396800 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 21025396800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39383992098).

21025396800 is an abundant number, since it is smaller than the sum of its proper divisors (57742587396).

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

21025396800 is a wasteful number, since it uses less digits than its factorization.

21025396800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3148 (or 3124 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 36.

The spelling of 21025396800 in words is "twenty-one billion, twenty-five million, three hundred ninety-six thousand, eight hundred".