11571891 has 4 divisors (see below), whose sum is σ = 15429192. Its totient is φ = 7714592.

The previous prime is 11571851. The next prime is 11571913. The reversal of 11571891 is 19817511.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 11571891 - 2⁹ = 11571379 is a prime.

It is a super-2 number, since 2×11571891² = 267817322631762, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (11571811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1928646 + ... + 1928651.

It is an arithmetic number, because the mean of its divisors is an integer number (3857298).

Almost surely, 2^11571891 is an apocalyptic number.

11571891 is a deficient number, since it is larger than the sum of its proper divisors (3857301).

11571891 is an equidigital number, since it uses as much as digits as its factorization.

11571891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3857300.

The product of its digits is 2520, while the sum is 33.

The square root of 11571891 is about 3401.7482270150. The cubic root of 11571891 is about 226.1872452960.

The spelling of 11571891 in words is "eleven million, five hundred seventy-one thousand, eight hundred ninety-one".