77770861 has 4 divisors (see below), whose sum is σ = 88880992. Its totient is φ = 66660732.

The previous prime is 77770829. The next prime is 77770877. The reversal of 77770861 is 16807777.

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, and also an emirpimes, since its reverse is a distinct semiprime: 16807777 = 7 ⋅2401111.

It is a cyclic number.

It is not a de Polignac number, because 77770861 - 2⁵ = 77770829 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 (77771861) 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, 5555055 + ... + 5555068.

It is an arithmetic number, because the mean of its divisors is an integer number (22220248).

Almost surely, 2^77770861 is an apocalyptic number.

It is an amenable number.

77770861 is a deficient number, since it is larger than the sum of its proper divisors (11110131).

77770861 is a wasteful number, since it uses less digits than its factorization.

77770861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11110130.

The product of its (nonzero) digits is 115248, while the sum is 43.

The square root of 77770861 is about 8818.7788837231. The cubic root of 77770861 is about 426.8470677424.

The spelling of 77770861 in words is "seventy-seven million, seven hundred seventy thousand, eight hundred sixty-one".