78891872999 has 4 divisors (see below), whose sum is σ = 81436772160. Its totient is φ = 76346973840.

The previous prime is 78891872957. The next prime is 78891873013. The reversal of 78891872999 is 99927819887.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78891872999 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78891872099) 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, 1272449534 + ... + 1272449595.

It is an arithmetic number, because the mean of its divisors is an integer number (20359193040).

Almost surely, 2^78891872999 is an apocalyptic number.

78891872999 is a deficient number, since it is larger than the sum of its proper divisors (2544899161).

78891872999 is a wasteful number, since it uses less digits than its factorization.

78891872999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2544899160.

The product of its digits is 329204736, while the sum is 77.

The spelling of 78891872999 in words is "seventy-eight billion, eight hundred ninety-one million, eight hundred seventy-two thousand, nine hundred ninety-nine".