11951591 has 2 divisors, whose sum is σ = 11951592. Its totient is φ = 11951590.

The previous prime is 11951557. The next prime is 11951593. The reversal of 11951591 is 19515911.

It is a strong prime.

It is an emirp because it is prime and its reverse (19515911) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11951591 is a prime.

It is a Sophie Germain prime.

Together with 11951593, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11951593) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5975795 + 5975796.

It is an arithmetic number, because the mean of its divisors is an integer number (5975796).

Almost surely, 2^11951591 is an apocalyptic number.

11951591 is a deficient number, since it is larger than the sum of its proper divisors (1).

11951591 is an equidigital number, since it uses as much as digits as its factorization.

11951591 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2025, while the sum is 32.

The square root of 11951591 is about 3457.1073168185. The cubic root of 11951591 is about 228.6345754287.

The spelling of 11951591 in words is "eleven million, nine hundred fifty-one thousand, five hundred ninety-one".