77807979 has 16 divisors (see below), whose sum is σ = 115479040. Its totient is φ = 51778440.

The previous prime is 77807927. The next prime is 77807987. The reversal of 77807979 is 97970877.

It is not a de Polignac number, because 77807979 - 2⁹ = 77807467 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77807909) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14754 + ... + 19320.

It is an arithmetic number, because the mean of its divisors is an integer number (7217440).

Almost surely, 2^77807979 is an apocalyptic number.

77807979 is a deficient number, since it is larger than the sum of its proper divisors (37671061).

77807979 is a wasteful number, since it uses less digits than its factorization.

77807979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5207 (or 5201 counting only the distinct ones).

The product of its (nonzero) digits is 1555848, while the sum is 54.

The square root of 77807979 is about 8820.8831190533. The cubic root of 77807979 is about 426.9149645927.

The spelling of 77807979 in words is "seventy-seven million, eight hundred seven thousand, nine hundred seventy-nine".