11525991 has 4 divisors (see below), whose sum is σ = 15367992. Its totient is φ = 7683992.

The previous prime is 11525977. The next prime is 11525993. The reversal of 11525991 is 19952511.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19952511 = 3 ⋅6650837.

It is a cyclic number.

It is not a de Polignac number, because 11525991 - 2⁵ = 11525959 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11525993) 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, 1920996 + ... + 1921001.

It is an arithmetic number, because the mean of its divisors is an integer number (3841998).

Almost surely, 2^11525991 is an apocalyptic number.

11525991 is a deficient number, since it is larger than the sum of its proper divisors (3842001).

11525991 is an equidigital number, since it uses as much as digits as its factorization.

11525991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3842000.

The product of its digits is 4050, while the sum is 33.

The square root of 11525991 is about 3394.9949926325. The cubic root of 11525991 is about 225.8877911663.

It can be divided in two parts, 115 and 25991, that added together give a triangular number (26106 = T₂₂₈).

The spelling of 11525991 in words is "eleven million, five hundred twenty-five thousand, nine hundred ninety-one".