78681577 has 4 divisors (see below), whose sum is σ = 84734020. Its totient is φ = 72629136.

The previous prime is 78681571. The next prime is 78681587. The reversal of 78681577 is 77518687.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 77518687 = 191 ⋅405857.

It can be written as a sum of positive squares in 2 ways, for example, as 28611801 + 50069776 = 5349^2 + 7076^2 .

It is a cyclic number.

It is not a de Polignac number, because 78681577 - 2³ = 78681569 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 78681577.

It is not an unprimeable number, because it can be changed into a prime (78681571) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3026202 + ... + 3026227.

It is an arithmetic number, because the mean of its divisors is an integer number (21183505).

Almost surely, 2^78681577 is an apocalyptic number.

It is an amenable number.

78681577 is a deficient number, since it is larger than the sum of its proper divisors (6052443).

78681577 is a wasteful number, since it uses less digits than its factorization.

78681577 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6052442.

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

The square root of 78681577 is about 8870.2636375702. The cubic root of 78681577 is about 428.5067675516.

The spelling of 78681577 in words is "seventy-eight million, six hundred eighty-one thousand, five hundred seventy-seven".