78936778 has 4 divisors (see below), whose sum is σ = 118405170. Its totient is φ = 39468388.

The previous prime is 78936743. The next prime is 78936817. The reversal of 78936778 is 87763987.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 87763987 = 811 ⋅108217.

It can be written as a sum of positive squares in only one way, i.e., 54066609 + 24870169 = 7353^2 + 4987^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19734193 + ... + 19734196.

Almost surely, 2^78936778 is an apocalyptic number.

78936778 is a deficient number, since it is larger than the sum of its proper divisors (39468392).

78936778 is a wasteful number, since it uses less digits than its factorization.

78936778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39468391.

The product of its digits is 3556224, while the sum is 55.

The square root of 78936778 is about 8884.6371901164. The cubic root of 78936778 is about 428.9695499132.

The spelling of 78936778 in words is "seventy-eight million, nine hundred thirty-six thousand, seven hundred seventy-eight".