131191891 has 2 divisors, whose sum is σ = 131191892. Its totient is φ = 131191890.

The previous prime is 131191871. The next prime is 131191897. The reversal of 131191891 is 198191131.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 131191891 - 2⁵ = 131191859 is a prime.

It is a super-2 number, since 2×131191891² = 34422624528311762, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (131191897) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 65595945 + 65595946.

It is an arithmetic number, because the mean of its divisors is an integer number (65595946).

Almost surely, 2^131191891 is an apocalyptic number.

131191891 is a deficient number, since it is larger than the sum of its proper divisors (1).

131191891 is an equidigital number, since it uses as much as digits as its factorization.

131191891 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1944, while the sum is 34.

The square root of 131191891 is about 11453.9028719472. The cubic root of 131191891 is about 508.1231682560.

The spelling of 131191891 in words is "one hundred thirty-one million, one hundred ninety-one thousand, eight hundred ninety-one".