77865861 has 4 divisors (see below), whose sum is σ = 103821152. Its totient is φ = 51910572.

The previous prime is 77865839. The next prime is 77865863. The reversal of 77865861 is 16856877.

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 not a de Polignac number, because 77865861 - 2¹⁸ = 77603717 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 77865861.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77865863) 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, 12977641 + ... + 12977646.

It is an arithmetic number, because the mean of its divisors is an integer number (25955288).

Almost surely, 2^77865861 is an apocalyptic number.

It is an amenable number.

77865861 is a deficient number, since it is larger than the sum of its proper divisors (25955291).

77865861 is a wasteful number, since it uses less digits than its factorization.

77865861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25955290.

The product of its digits is 564480, while the sum is 48.

The square root of 77865861 is about 8824.1634731004. The cubic root of 77865861 is about 427.0208002124.

The spelling of 77865861 in words is "seventy-seven million, eight hundred sixty-five thousand, eight hundred sixty-one".