77974891 has 2 divisors, whose sum is σ = 77974892. Its totient is φ = 77974890.

The previous prime is 77974789. The next prime is 77974901. The reversal of 77974891 is 19847977.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 77974891 - 2⁷ = 77974763 is a prime.

It is not a weakly prime, because it can be changed into another prime (77971891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38987445 + 38987446.

It is an arithmetic number, because the mean of its divisors is an integer number (38987446).

Almost surely, 2^77974891 is an apocalyptic number.

77974891 is a deficient number, since it is larger than the sum of its proper divisors (1).

77974891 is an equidigital number, since it uses as much as digits as its factorization.

77974891 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 889056, while the sum is 52.

The square root of 77974891 is about 8830.3392347067. The cubic root of 77974891 is about 427.2200161610.

The spelling of 77974891 in words is "seventy-seven million, nine hundred seventy-four thousand, eight hundred ninety-one".