78861577 has 2 divisors, whose sum is σ = 78861578. Its totient is φ = 78861576.

The previous prime is 78861569. The next prime is 78861599. The reversal of 78861577 is 77516887.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 75707401 + 3154176 = 8701^2 + 1776^2 .

It is a cyclic number.

It is not a de Polignac number, because 78861577 - 2³ = 78861569 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 78861577.

It is not a weakly prime, because it can be changed into another prime (78861557) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39430788 + 39430789.

It is an arithmetic number, because the mean of its divisors is an integer number (39430789).

Almost surely, 2^78861577 is an apocalyptic number.

It is an amenable number.

78861577 is a deficient number, since it is larger than the sum of its proper divisors (1).

78861577 is an equidigital number, since it uses as much as digits as its factorization.

78861577 is an evil number, because the sum of its binary digits is even.

The product of its digits is 658560, while the sum is 49.

The square root of 78861577 is about 8880.4041011657. The cubic root of 78861577 is about 428.8332839484.

The spelling of 78861577 in words is "seventy-eight million, eight hundred sixty-one thousand, five hundred seventy-seven".