78997766 has 4 divisors (see below), whose sum is σ = 118496652. Its totient is φ = 39498882.

The previous prime is 78997747. The next prime is 78997771. The reversal of 78997766 is 66779987.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19749440 + ... + 19749443.

It is an arithmetic number, because the mean of its divisors is an integer number (29624163).

Almost surely, 2^78997766 is an apocalyptic number.

78997766 is a deficient number, since it is larger than the sum of its proper divisors (39498886).

78997766 is a wasteful number, since it uses less digits than its factorization.

78997766 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39498885.

The product of its digits is 8001504, while the sum is 59.

The square root of 78997766 is about 8888.0687441086. The cubic root of 78997766 is about 429.0799980495.

The spelling of 78997766 in words is "seventy-eight million, nine hundred ninety-seven thousand, seven hundred sixty-six".