91779 has 4 divisors (see below), whose sum is σ = 122376. Its totient is φ = 61184.

The previous prime is 91771. The next prime is 91781. The reversal of 91779 is 97719.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 97719 = 3 ⋅32573.

It is a cyclic number.

It is not a de Polignac number, because 91779 - 2³ = 91771 is a prime.

It is a D-number.

91779 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (91771) 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, 15294 + ... + 15299.

It is an arithmetic number, because the mean of its divisors is an integer number (30594).

2⁹¹⁷⁷⁹ is an apocalyptic number.

91779 is a deficient number, since it is larger than the sum of its proper divisors (30597).

91779 is a wasteful number, since it uses less digits than its factorization.

91779 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30596.

The product of its digits is 3969, while the sum is 33.

The square root of 91779 is about 302.9504910047. The cubic root of 91779 is about 45.1073977996.

The spelling of 91779 in words is "ninety-one thousand, seven hundred seventy-nine".