78812517881 has 4 divisors (see below), whose sum is σ = 78873947472. Its totient is φ = 78751088292.

The previous prime is 78812517869. The next prime is 78812517913. The reversal of 78812517881 is 18871521887.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 78812517881 - 2²² = 78808323577 is a prime.

It is a super-2 number, since 2×78812517881² (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 (78812517811) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30712871 + ... + 30715436.

It is an arithmetic number, because the mean of its divisors is an integer number (19718486868).

Almost surely, 2^78812517881 is an apocalyptic number.

It is an amenable number.

78812517881 is a deficient number, since it is larger than the sum of its proper divisors (61429591).

78812517881 is a wasteful number, since it uses less digits than its factorization.

78812517881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61429590.

The product of its digits is 2007040, while the sum is 56.

The spelling of 78812517881 in words is "seventy-eight billion, eight hundred twelve million, five hundred seventeen thousand, eight hundred eighty-one".