21408831360 has 320 divisors, whose sum is σ = 87378397920. Its totient is φ = 4893364224.

The previous prime is 21408831359. The next prime is 21408831377. The reversal of 21408831360 is 6313880412.

21408831360 is a `hidden beast` number, since 214 + 0 + 8 + 83 + 1 + 360 = 666.

It is a tau number, because it is divible by the number of its divisors (320).

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 39 ways as a sum of consecutive naturals, for example, 333382 + ... + 392378.

Almost surely, 2^21408831360 is an apocalyptic number.

21408831360 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 21408831360, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43689198960).

21408831360 is an abundant number, since it is smaller than the sum of its proper divisors (65969566560).

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

21408831360 is an equidigital number, since it uses as much as digits as its factorization.

21408831360 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59035 (or 59014 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 36.

The spelling of 21408831360 in words is "twenty-one billion, four hundred eight million, eight hundred thirty-one thousand, three hundred sixty".