78113891 has 4 divisors (see below), whose sum is σ = 79587792. Its totient is φ = 76639992.

The previous prime is 78113887. The next prime is 78113909. The reversal of 78113891 is 19831187.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19831187 = 353 ⋅56179.

It is a cyclic number.

It is not a de Polignac number, because 78113891 - 2² = 78113887 is a prime.

It is a super-2 number, since 2×78113891² = 12203559934319762, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78113801) 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, 736871 + ... + 736976.

It is an arithmetic number, because the mean of its divisors is an integer number (19896948).

Almost surely, 2^78113891 is an apocalyptic number.

78113891 is a deficient number, since it is larger than the sum of its proper divisors (1473901).

78113891 is a wasteful number, since it uses less digits than its factorization.

78113891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1473900.

The product of its digits is 12096, while the sum is 38.

The square root of 78113891 is about 8838.2063225521. The cubic root of 78113891 is about 427.4737231777.

The spelling of 78113891 in words is "seventy-eight million, one hundred thirteen thousand, eight hundred ninety-one".