21321858965400 has 768 divisors, whose sum is σ = 85656124800000. Its totient is φ = 4774454046720.

The previous prime is 21321858965389. The next prime is 21321858965413. The reversal of 21321858965400 is 456985812312.

21321858965400 is a `hidden beast` number, since 2 + 1 + 3 + 2 + 1 + 8 + 5 + 8 + 96 + 540 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 411124671 + ... + 411176529.

It is an arithmetic number, because the mean of its divisors is an integer number (111531412500).

Almost surely, 2^{21321858965400} is an apocalyptic number.

21321858965400 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 21321858965400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42828062400000).

21321858965400 is an abundant number, since it is smaller than the sum of its proper divisors (64334265834600).

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

21321858965400 is a wasteful number, since it uses less digits than its factorization.

21321858965400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52113 (or 52098 counting only the distinct ones).

The product of its (nonzero) digits is 4147200, while the sum is 54.

The spelling of 21321858965400 in words is "twenty-one trillion, three hundred twenty-one billion, eight hundred fifty-eight million, nine hundred sixty-five thousand, four hundred".