91581379 has 4 divisors (see below), whose sum is σ = 91600576. Its totient is φ = 91562184.

The previous prime is 91581367. The next prime is 91581433. The reversal of 91581379 is 97318519.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 97318519 = 29 ⋅3355811.

It is a cyclic number.

It is not a de Polignac number, because 91581379 - 2⁷ = 91581251 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91581359) 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, 3697 + ... + 14029.

It is an arithmetic number, because the mean of its divisors is an integer number (22900144).

Almost surely, 2^91581379 is an apocalyptic number.

91581379 is a deficient number, since it is larger than the sum of its proper divisors (19197).

91581379 is a wasteful number, since it uses less digits than its factorization.

91581379 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19196.

The product of its digits is 68040, while the sum is 43.

The square root of 91581379 is about 9569.8160379393. The cubic root of 91581379 is about 450.7499904895.

The spelling of 91581379 in words is "ninety-one million, five hundred eighty-one thousand, three hundred seventy-nine".