11971391 has 4 divisors (see below), whose sum is σ = 11989752. Its totient is φ = 11953032.

The previous prime is 11971373. The next prime is 11971397. The reversal of 11971391 is 19317911.

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 11971391 - 2⁶ = 11971327 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11971397) 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, 8165 + ... + 9518.

It is an arithmetic number, because the mean of its divisors is an integer number (2997438).

Almost surely, 2^11971391 is an apocalyptic number.

11971391 is a deficient number, since it is larger than the sum of its proper divisors (18361).

11971391 is an equidigital number, since it uses as much as digits as its factorization.

11971391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18360.

The product of its digits is 1701, while the sum is 32.

The square root of 11971391 is about 3459.9697975560. The cubic root of 11971391 is about 228.7607641227.

The spelling of 11971391 in words is "eleven million, nine hundred seventy-one thousand, three hundred ninety-one".