21863656406400 has 768 divisors, whose sum is σ = 76326304803840. Its totient is φ = 5489761812480.

The previous prime is 21863656406393. The next prime is 21863656406479. The reversal of 21863656406400 is 460465636812.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 3934432422 + ... + 3934437978.

It is an arithmetic number, because the mean of its divisors is an integer number (99383209380).

Almost surely, 2^{21863656406400} is an apocalyptic number.

21863656406400 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 21863656406400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38163152401920).

21863656406400 is an abundant number, since it is smaller than the sum of its proper divisors (54462648397440).

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

21863656406400 is a wasteful number, since it uses less digits than its factorization.

21863656406400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5883 (or 5866 counting only the distinct ones).

The product of its (nonzero) digits is 4976640, while the sum is 51.

The spelling of 21863656406400 in words is "twenty-one trillion, eight hundred sixty-three billion, six hundred fifty-six million, four hundred six thousand, four hundred".