77816257 has 2 divisors, whose sum is σ = 77816258. Its totient is φ = 77816256.

The previous prime is 77816203. The next prime is 77816287. The reversal of 77816257 is 75261877.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 39425841 + 38390416 = 6279^2 + 6196^2 .

It is a cyclic number.

It is not a de Polignac number, because 77816257 - 2⁷ = 77816129 is a prime.

It is not a weakly prime, because it can be changed into another prime (77816287) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38908128 + 38908129.

It is an arithmetic number, because the mean of its divisors is an integer number (38908129).

Almost surely, 2^77816257 is an apocalyptic number.

It is an amenable number.

77816257 is a deficient number, since it is larger than the sum of its proper divisors (1).

77816257 is an equidigital number, since it uses as much as digits as its factorization.

77816257 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 164640, while the sum is 43.

The square root of 77816257 is about 8821.3523339678. The cubic root of 77816257 is about 426.9301039002.

The spelling of 77816257 in words is "seventy-seven million, eight hundred sixteen thousand, two hundred fifty-seven".