91779859 has 4 divisors (see below), whose sum is σ = 91816704. Its totient is φ = 91743016.

The previous prime is 91779847. The next prime is 91779911. The reversal of 91779859 is 95897719.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 95897719 = 47 ⋅2040377.

It is a cyclic number.

It is not a de Polignac number, because 91779859 - 2²¹ = 89682707 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91779829) 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, 14392 + ... + 19765.

It is an arithmetic number, because the mean of its divisors is an integer number (22954176).

Almost surely, 2^91779859 is an apocalyptic number.

91779859 is a deficient number, since it is larger than the sum of its proper divisors (36845).

91779859 is a wasteful number, since it uses less digits than its factorization.

91779859 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36844.

The product of its digits is 1428840, while the sum is 55.

The square root of 91779859 is about 9580.1805306581. The cubic root of 91779859 is about 451.0753852580.

The spelling of 91779859 in words is "ninety-one million, seven hundred seventy-nine thousand, eight hundred fifty-nine".