91091893 has 4 divisors (see below), whose sum is σ = 91809280. Its totient is φ = 90374508.

The previous prime is 91091887. The next prime is 91091921. The reversal of 91091893 is 39819019.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 39819019 = 197 ⋅202127.

It is a cyclic number.

It is not a de Polignac number, because 91091893 - 2²⁵ = 57537461 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 (91091393) 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, 358503 + ... + 358756.

It is an arithmetic number, because the mean of its divisors is an integer number (22952320).

Almost surely, 2^91091893 is an apocalyptic number.

It is an amenable number.

91091893 is a deficient number, since it is larger than the sum of its proper divisors (717387).

91091893 is a wasteful number, since it uses less digits than its factorization.

91091893 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 717386.

The product of its (nonzero) digits is 17496, while the sum is 40.

The square root of 91091893 is about 9544.2073007663. The cubic root of 91091893 is about 449.9454962795.

The spelling of 91091893 in words is "ninety-one million, ninety-one thousand, eight hundred ninety-three".