77491979 has 2 divisors, whose sum is σ = 77491980. Its totient is φ = 77491978.

The previous prime is 77491963. The next prime is 77492011. The reversal of 77491979 is 97919477.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 77491979 - 2⁴ = 77491963 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 77491979.

It is not a weakly prime, because it can be changed into another prime (77491919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38745989 + 38745990.

It is an arithmetic number, because the mean of its divisors is an integer number (38745990).

Almost surely, 2^77491979 is an apocalyptic number.

77491979 is a deficient number, since it is larger than the sum of its proper divisors (1).

77491979 is an equidigital number, since it uses as much as digits as its factorization.

77491979 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1000188, while the sum is 53.

The square root of 77491979 is about 8802.9528568543. The cubic root of 77491979 is about 426.3362400073.

The spelling of 77491979 in words is "seventy-seven million, four hundred ninety-one thousand, nine hundred seventy-nine".