21287407706400 has 288 divisors, whose sum is σ = 78196191998400. Its totient is φ = 4982632345600.

The previous prime is 21287407706399. The next prime is 21287407706401. The reversal of 21287407706400 is 460770478212.

It is an interprime number because it is at equal distance from previous prime (21287407706399) and next prime (21287407706401).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 21287407706400.

It is not an unprimeable number, because it can be changed into a prime (21287407706401) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 13136835 + ... + 14668034.

It is an arithmetic number, because the mean of its divisors is an integer number (271514555550).

Almost surely, 2^{21287407706400} is an apocalyptic number.

21287407706400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21287407706400 is an abundant number, since it is smaller than the sum of its proper divisors (56908784292000).

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

21287407706400 is a wasteful number, since it uses less digits than its factorization.

21287407706400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27804932 (or 27804919 counting only the distinct ones).

The product of its (nonzero) digits is 1053696, while the sum is 48.

The spelling of 21287407706400 in words is "twenty-one trillion, two hundred eighty-seven billion, four hundred seven million, seven hundred six thousand, four hundred".