22091591 has 4 divisors (see below), whose sum is σ = 22853400. Its totient is φ = 21329784.

The previous prime is 22091539. The next prime is 22091603. The reversal of 22091591 is 19519022.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19519022 = 2 ⋅9759511.

It is a cyclic number.

It is not a de Polignac number, because 22091591 - 2⁶ = 22091527 is a prime.

It is a super-2 number, since 2×22091591² = 976076785822562, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (29), and also a Moran number because the ratio is a prime number: 761779 = 22091591 / (2 + 2 + 0 + 9 + 1 + 5 + 9 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22091501) 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, 380861 + ... + 380918.

It is an arithmetic number, because the mean of its divisors is an integer number (5713350).

Almost surely, 2^22091591 is an apocalyptic number.

22091591 is a deficient number, since it is larger than the sum of its proper divisors (761809).

22091591 is an equidigital number, since it uses as much as digits as its factorization.

22091591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 761808.

The product of its (nonzero) digits is 1620, while the sum is 29.

The square root of 22091591 is about 4700.1692522717. The cubic root of 22091591 is about 280.5922455707.

The spelling of 22091591 in words is "twenty-two million, ninety-one thousand, five hundred ninety-one".