77906 has 4 divisors (see below), whose sum is σ = 116862. Its totient is φ = 38952.

The previous prime is 77899. The next prime is 77929. The reversal of 77906 is 60977.

77906 = 75² + 76² + ... + 86².

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 43681 + 34225 = 209^2 + 185^2 .

It is a nialpdrome in base 5.

It is an unprimeable number.

77906 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19475 + ... + 19478.

2⁷⁷⁹⁰⁶ is an apocalyptic number.

77906 is a deficient number, since it is larger than the sum of its proper divisors (38956).

77906 is a wasteful number, since it uses less digits than its factorization.

77906 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38955.

The product of its (nonzero) digits is 2646, while the sum is 29.

The square root of 77906 is about 279.1164631476. The cubic root of 77906 is about 42.7094162459.

Subtracting from 77906 its sum of digits (29), we obtain a palindrome (77877).

The spelling of 77906 in words is "seventy-seven thousand, nine hundred six".