78542657 has 2 divisors, whose sum is σ = 78542658. Its totient is φ = 78542656.

The previous prime is 78542627. The next prime is 78542689. The reversal of 78542657 is 75624587.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 78127921 + 414736 = 8839^2 + 644^2 .

It is a cyclic number.

It is not a de Polignac number, because 78542657 - 2¹⁰ = 78541633 is a prime.

It is not a weakly prime, because it can be changed into another prime (78542617) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39271328 + 39271329.

It is an arithmetic number, because the mean of its divisors is an integer number (39271329).

Almost surely, 2^78542657 is an apocalyptic number.

It is an amenable number.

78542657 is a deficient number, since it is larger than the sum of its proper divisors (1).

78542657 is an equidigital number, since it uses as much as digits as its factorization.

78542657 is an evil number, because the sum of its binary digits is even.

The product of its digits is 470400, while the sum is 44.

The square root of 78542657 is about 8862.4295201711. The cubic root of 78542657 is about 428.2544288166.

The spelling of 78542657 in words is "seventy-eight million, five hundred forty-two thousand, six hundred fifty-seven".