21613478400 has 240 divisors, whose sum is σ = 79333240800. Its totient is φ = 5763502080.

The previous prime is 21613478399. The next prime is 21613478429. The reversal of 21613478400 is 487431612.

21613478400 is a `hidden beast` number, since 216 + 1 + 34 + 7 + 8 + 400 = 666.

It is a tau number, because it is divible by the number of its divisors (240).

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

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 314331 + ... + 376869.

It is an arithmetic number, because the mean of its divisors is an integer number (330555170).

Almost surely, 2^21613478400 is an apocalyptic number.

21613478400 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 21613478400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39666620400).

21613478400 is an abundant number, since it is smaller than the sum of its proper divisors (57719762400).

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

21613478400 is an equidigital number, since it uses as much as digits as its factorization.

21613478400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62576 (or 62549 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 36.

The spelling of 21613478400 in words is "twenty-one billion, six hundred thirteen million, four hundred seventy-eight thousand, four hundred".