78831476721 has 16 divisors (see below), whose sum is σ = 116792193600. Its totient is φ = 52552148544.

The previous prime is 78831476693. The next prime is 78831476783. The reversal of 78831476721 is 12767413887.

78831476721 is a `hidden beast` number, since 78 + 8 + 31 + 476 + 72 + 1 = 666.

It is not a de Polignac number, because 78831476721 - 2²¹ = 78829379569 is a prime.

It is not an unprimeable number, because it can be changed into a prime (78831476821) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 863385 + ... + 950313.

It is an arithmetic number, because the mean of its divisors is an integer number (7299512100).

Almost surely, 2^78831476721 is an apocalyptic number.

It is an amenable number.

78831476721 is a deficient number, since it is larger than the sum of its proper divisors (37960716879).

78831476721 is a wasteful number, since it uses less digits than its factorization.

78831476721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120525 (or 120519 counting only the distinct ones).

The product of its digits is 3161088, while the sum is 54.

The spelling of 78831476721 in words is "seventy-eight billion, eight hundred thirty-one million, four hundred seventy-six thousand, seven hundred twenty-one".