21408774400 has 432 divisors, whose sum is σ = 62274139200. Its totient is φ = 7215022080.

The previous prime is 21408774391. The next prime is 21408774467. The reversal of 21408774400 is 447780412.

It is a self number, because there is not a number n which added to its sum of digits gives 21408774400.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 45842967 + ... + 45843433.

It is an arithmetic number, because the mean of its divisors is an integer number (144153100).

Almost surely, 2^21408774400 is an apocalyptic number.

21408774400 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 21408774400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31137069600).

21408774400 is an abundant number, since it is smaller than the sum of its proper divisors (40865364800).

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

21408774400 is a wasteful number, since it uses less digits than its factorization.

21408774400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 554 (or 535 counting only the distinct ones).

The product of its (nonzero) digits is 50176, while the sum is 37.

The spelling of 21408774400 in words is "twenty-one billion, four hundred eight million, seven hundred seventy-four thousand, four hundred".