78108397897 has 24 divisors (see below), whose sum is σ = 85461336216. Its totient is φ = 71320854528.

The previous prime is 78108397859. The next prime is 78108397907. The reversal of 78108397897 is 79879380187.

It can be written as a sum of positive squares in 12 ways, for example, as 7509782281 + 70598615616 = 86659^2 + 265704^2 .

It is not a de Polignac number, because 78108397897 - 2⁷ = 78108397769 is a prime.

It is a super-2 number, since 2×78108397897² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78108397397) 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 in 23 ways as a sum of consecutive naturals, for example, 3764283 + ... + 3784975.

It is an arithmetic number, because the mean of its divisors is an integer number (3560889009).

Almost surely, 2^78108397897 is an apocalyptic number.

It is an amenable number.

78108397897 is a deficient number, since it is larger than the sum of its proper divisors (7352938319).

78108397897 is a wasteful number, since it uses less digits than its factorization.

78108397897 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21117 (or 21100 counting only the distinct ones).

The product of its (nonzero) digits is 42674688, while the sum is 67.

The spelling of 78108397897 in words is "seventy-eight billion, one hundred eight million, three hundred ninety-seven thousand, eight hundred ninety-seven".