77908015217 has 2 divisors, whose sum is σ = 77908015218. Its totient is φ = 77908015216.

The previous prime is 77908015181. The next prime is 77908015223. The reversal of 77908015217 is 71251080977.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 73681845136 + 4226170081 = 271444^2 + 65009^2 .

It is a cyclic number.

It is not a de Polignac number, because 77908015217 - 2¹⁰ = 77908014193 is a prime.

It is not a weakly prime, because it can be changed into another prime (77908015247) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38954007608 + 38954007609.

It is an arithmetic number, because the mean of its divisors is an integer number (38954007609).

Almost surely, 2^77908015217 is an apocalyptic number.

It is an amenable number.

77908015217 is a deficient number, since it is larger than the sum of its proper divisors (1).

77908015217 is an equidigital number, since it uses as much as digits as its factorization.

77908015217 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 246960, while the sum is 47.

The spelling of 77908015217 in words is "seventy-seven billion, nine hundred eight million, fifteen thousand, two hundred seventeen".