77939 has 4 divisors (see below), whose sum is σ = 79320. Its totient is φ = 76560.

The previous prime is 77933. The next prime is 77951. The reversal of 77939 is 93977.

77939 = T₁₉ + T₂₀ + ... + T₇₇.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 93977 = 13 ⋅7229.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-77939 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 77899 and 77908.

It is not an unprimeable number, because it can be changed into a prime (77933) 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, 602 + ... + 719.

It is an arithmetic number, because the mean of its divisors is an integer number (19830).

2⁷⁷⁹³⁹ is an apocalyptic number.

77939 is a deficient number, since it is larger than the sum of its proper divisors (1381).

77939 is a wasteful number, since it uses less digits than its factorization.

77939 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1380.

The product of its digits is 11907, while the sum is 35.

The square root of 77939 is about 279.1755719973. The cubic root of 77939 is about 42.7154457849.

It can be divided in two parts, 779 and 39, that multiplied together give a triangular number (30381 = T₂₄₆).

The spelling of 77939 in words is "seventy-seven thousand, nine hundred thirty-nine".