21215416320 has 1092 divisors, whose sum is σ = 91855348380. Its totient is φ = 4682022912.

The previous prime is 21215416279. The next prime is 21215416331. The reversal of 21215416320 is 2361451212.

21215416320 is a `hidden beast` number, since 2 + 1 + 21 + 5 + 4 + 1 + 632 + 0 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 9364045824 + 11851370496 = 96768^2 + 108864^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 83 ways as a sum of consecutive naturals, for example, 731566066 + ... + 731566094.

Almost surely, 2^21215416320 is an apocalyptic number.

21215416320 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 21215416320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45927674190).

21215416320 is an abundant number, since it is smaller than the sum of its proper divisors (70639932060).

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

21215416320 is an frugal number, since it uses more digits than its factorization.

21215416320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90 (or 46 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

Adding to 21215416320 its reverse (2361451212), we get a palindrome (23576867532).

The spelling of 21215416320 in words is "twenty-one billion, two hundred fifteen million, four hundred sixteen thousand, three hundred twenty".