77797891 has 4 divisors (see below), whose sum is σ = 81180432. Its totient is φ = 74415352.

The previous prime is 77797873. The next prime is 77797897. The reversal of 77797891 is 19879777.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19879777 = 2689 ⋅7393.

It is a cyclic number.

It is not a de Polignac number, because 77797891 - 2⁵ = 77797859 is a prime.

It is not an unprimeable number, because it can be changed into a prime (77797897) 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, 1691236 + ... + 1691281.

It is an arithmetic number, because the mean of its divisors is an integer number (20295108).

Almost surely, 2^77797891 is an apocalyptic number.

77797891 is a deficient number, since it is larger than the sum of its proper divisors (3382541).

77797891 is a wasteful number, since it uses less digits than its factorization.

77797891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3382540.

The product of its digits is 1555848, while the sum is 55.

The square root of 77797891 is about 8820.3112756864. The cubic root of 77797891 is about 426.8965135960.

The spelling of 77797891 in words is "seventy-seven million, seven hundred ninety-seven thousand, eight hundred ninety-one".