21320294400 has 504 divisors, whose sum is σ = 78435906120. Its totient is φ = 5532549120.

The previous prime is 21320294399. The next prime is 21320294431. The reversal of 21320294400 is 449202312.

21320294400 is a `hidden beast` number, since 2 + 13 + 202 + 9 + 440 + 0 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 79257466 + ... + 79257734.

Almost surely, 2^21320294400 is an apocalyptic number.

21320294400 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 21320294400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39217953060).

21320294400 is an abundant number, since it is smaller than the sum of its proper divisors (57115611720).

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

21320294400 is a wasteful number, since it uses less digits than its factorization.

21320294400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 354 (or 322 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

Adding to 21320294400 its reverse (449202312), we get a palindrome (21769496712).

The spelling of 21320294400 in words is "twenty-one billion, three hundred twenty million, two hundred ninety-four thousand, four hundred".