99779 has 4 divisors (see below), whose sum is σ = 100776. Its totient is φ = 98784.

The previous prime is 99767. The next prime is 99787. The reversal of 99779 is 97799.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 97799 = 13 ⋅7523.

It is a cyclic number.

It is not a de Polignac number, because 99779 - 2⁸ = 99523 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (99709) 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, 329 + ... + 554.

It is an arithmetic number, because the mean of its divisors is an integer number (25194).

2⁹⁹⁷⁷⁹ is an apocalyptic number.

99779 is a deficient number, since it is larger than the sum of its proper divisors (997).

99779 is a wasteful number, since it uses less digits than its factorization.

99779 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 996.

The product of its digits is 35721, while the sum is 41.

The square root of 99779 is about 315.8781410608. The cubic root of 99779 is about 46.3816700785.

It can be divided in two parts, 99 and 779, that added together give a palindrome (878).

The spelling of 99779 in words is "ninety-nine thousand, seven hundred seventy-nine".