77966978 has 4 divisors (see below), whose sum is σ = 116950470. Its totient is φ = 38983488.

The previous prime is 77966957. The next prime is 77966989. The reversal of 77966978 is 87966977.

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

It can be written as a sum of positive squares in only one way, i.e., 61669609 + 16297369 = 7853^2 + 4037^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19491743 + ... + 19491746.

Almost surely, 2^77966978 is an apocalyptic number.

77966978 is a deficient number, since it is larger than the sum of its proper divisors (38983492).

77966978 is a wasteful number, since it uses less digits than its factorization.

77966978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38983491.

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

The square root of 77966978 is about 8829.8911658072. The cubic root of 77966978 is about 427.2055640457.

Subtracting 77966978 from its reverse (87966977), we obtain a palindrome (9999999).

The spelling of 77966978 in words is "seventy-seven million, nine hundred sixty-six thousand, nine hundred seventy-eight".