77979551 has 4 divisors (see below), whose sum is σ = 83977992. Its totient is φ = 71981112.

The previous prime is 77979547. The next prime is 77979563. The reversal of 77979551 is 15597977.

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

It is a cyclic number.

It is not a de Polignac number, because 77979551 - 2² = 77979547 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 77979551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77979751) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2999201 + ... + 2999226.

It is an arithmetic number, because the mean of its divisors is an integer number (20994498).

Almost surely, 2^77979551 is an apocalyptic number.

77979551 is a deficient number, since it is larger than the sum of its proper divisors (5998441).

77979551 is a wasteful number, since it uses less digits than its factorization.

77979551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5998440.

The product of its digits is 694575, while the sum is 50.

The square root of 77979551 is about 8830.6030937870. The cubic root of 77979551 is about 427.2285266169.

The spelling of 77979551 in words is "seventy-seven million, nine hundred seventy-nine thousand, five hundred fifty-one".