21439393566768 has 80 divisors (see below), whose sum is σ = 61599274581600. Its totient is φ = 7139464899840.

The previous prime is 21439393566749. The next prime is 21439393566797. The reversal of 21439393566768 is 86766539393412.

21439393566768 is a `hidden beast` number, since 2 + 1 + 439 + 39 + 35 + 66 + 76 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a junction number, because it is equal to n+sod(n) for n = 21439393566696 and 21439393566705.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23862663 + ... + 24744806.

It is an arithmetic number, because the mean of its divisors is an integer number (769990932270).

Almost surely, 2^{21439393566768} is an apocalyptic number.

It is an amenable number.

21439393566768 is an abundant number, since it is smaller than the sum of its proper divisors (40159881014832).

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

21439393566768 is a wasteful number, since it uses less digits than its factorization.

21439393566768 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48608507 (or 48608495 counting only the distinct ones).

The product of its digits is 1058158080, while the sum is 72.

The spelling of 21439393566768 in words is "twenty-one trillion, four hundred thirty-nine billion, three hundred ninety-three million, five hundred sixty-six thousand, seven hundred sixty-eight".