91855819 has 12 divisors (see below), whose sum is σ = 101553480. Its totient is φ = 83019200.

The previous prime is 91855817. The next prime is 91855843.

91855819 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 91855819 - 2¹ = 91855817 is a prime.

It is a super-2 number, since 2×91855819² = 16874982968321522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91855817) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 19539 + ... + 23779.

It is an arithmetic number, because the mean of its divisors is an integer number (8462790).

Almost surely, 2^91855819 is an apocalyptic number.

91855819 is a deficient number, since it is larger than the sum of its proper divisors (9697661).

91855819 is a wasteful number, since it uses less digits than its factorization.

91855819 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4442 (or 4431 counting only the distinct ones).

The product of its digits is 129600, while the sum is 46.

The square root of 91855819 is about 9584.1441454102. The cubic root of 91855819 is about 451.1997925023.

The spelling of 91855819 in words is "ninety-one million, eight hundred fifty-five thousand, eight hundred nineteen".