78971533517 has 16 divisors (see below), whose sum is σ = 80376085680. Its totient is φ = 77576320512.

The previous prime is 78971533507. The next prime is 78971533579. The reversal of 78971533517 is 71533517987.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 15782645641 + 63188887876 = 125629^2 + 251374^2 .

It is a cyclic number.

It is not a de Polignac number, because 78971533517 - 2⁸ = 78971533261 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78971533507) 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, 27145859 + ... + 27148767.

It is an arithmetic number, because the mean of its divisors is an integer number (5023505355).

Almost surely, 2^78971533517 is an apocalyptic number.

It is an amenable number.

78971533517 is a deficient number, since it is larger than the sum of its proper divisors (1404552163).

78971533517 is a wasteful number, since it uses less digits than its factorization.

78971533517 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4352.

The product of its digits is 5556600, while the sum is 56.

The spelling of 78971533517 in words is "seventy-eight billion, nine hundred seventy-one million, five hundred thirty-three thousand, five hundred seventeen".