77639 has 4 divisors (see below), whose sum is σ = 82224. Its totient is φ = 73056.

The previous prime is 77621. The next prime is 77641. The reversal of 77639 is 93677.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 93677 = 113 ⋅829.

It is a cyclic number.

It is not a de Polignac number, because 77639 - 2⁸ = 77383 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 (77659) 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, 2267 + ... + 2300.

It is an arithmetic number, because the mean of its divisors is an integer number (20556).

2⁷⁷⁶³⁹ is an apocalyptic number.

77639 is a deficient number, since it is larger than the sum of its proper divisors (4585).

77639 is a wasteful number, since it uses less digits than its factorization.

77639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4584.

The product of its digits is 7938, while the sum is 32.

The square root of 77639 is about 278.6377576711. The cubic root of 77639 is about 42.6605690613.

The spelling of 77639 in words is "seventy-seven thousand, six hundred thirty-nine".