77905 has 4 divisors (see below), whose sum is σ = 93492. Its totient is φ = 62320.

The previous prime is 77899. The next prime is 77929. The reversal of 77905 is 50977.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 50977 = 19 ⋅2683.

It can be written as a sum of positive squares in 2 ways, for example, as 25921 + 51984 = 161^2 + 228^2 .

It is not a de Polignac number, because 77905 - 2¹⁵ = 45137 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 5.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7786 + ... + 7795.

It is an arithmetic number, because the mean of its divisors is an integer number (23373).

2⁷⁷⁹⁰⁵ is an apocalyptic number.

It is an amenable number.

77905 is a deficient number, since it is larger than the sum of its proper divisors (15587).

77905 is a wasteful number, since it uses less digits than its factorization.

77905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15586.

The product of its (nonzero) digits is 2205, while the sum is 28.

The square root of 77905 is about 279.1146717749. The cubic root of 77905 is about 42.7092335060.

Subtracting from 77905 its sum of digits (28), we obtain a palindrome (77877).

The spelling of 77905 in words is "seventy-seven thousand, nine hundred five".