131866991 has 2 divisors, whose sum is σ = 131866992. Its totient is φ = 131866990.

The previous prime is 131866961. The next prime is 131867009. The reversal of 131866991 is 199668131.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-131866991 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (131866961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 65933495 + 65933496.

It is an arithmetic number, because the mean of its divisors is an integer number (65933496).

Almost surely, 2^131866991 is an apocalyptic number.

131866991 is a deficient number, since it is larger than the sum of its proper divisors (1).

131866991 is an equidigital number, since it uses as much as digits as its factorization.

131866991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 69984, while the sum is 44.

The square root of 131866991 is about 11483.3353604256. The cubic root of 131866991 is about 508.9932607057.

The spelling of 131866991 in words is "one hundred thirty-one million, eight hundred sixty-six thousand, nine hundred ninety-one".