78511216957 has 2 divisors, whose sum is σ = 78511216958. Its totient is φ = 78511216956.

The previous prime is 78511216951. The next prime is 78511217041. The reversal of 78511216957 is 75961211587.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 47879566596 + 30631650361 = 218814^2 + 175019^2 .

It is a cyclic number.

It is not a de Polignac number, because 78511216957 - 2⁷ = 78511216829 is a prime.

It is a super-2 number, since 2×78511216957² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78511216951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39255608478 + 39255608479.

It is an arithmetic number, because the mean of its divisors is an integer number (39255608479).

Almost surely, 2^78511216957 is an apocalyptic number.

It is an amenable number.

78511216957 is a deficient number, since it is larger than the sum of its proper divisors (1).

78511216957 is an equidigital number, since it uses as much as digits as its factorization.

78511216957 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1058400, while the sum is 52.

The spelling of 78511216957 in words is "seventy-eight billion, five hundred eleven million, two hundred sixteen thousand, nine hundred fifty-seven".