131999999 has 4 divisors (see below), whose sum is σ = 132037080. Its totient is φ = 131962920.

The previous prime is 131999969. The next prime is 132000007. The reversal of 131999999 is 999999131.

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 131999999 - 2⁸ = 131999743 is a prime.

It is a Duffinian number.

131999999 is a modest number, since divided by 99999 gives 1319 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (131999969) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12557 + ... + 20534.

It is an arithmetic number, because the mean of its divisors is an integer number (33009270).

Almost surely, 2^131999999 is an apocalyptic number.

131999999 is a deficient number, since it is larger than the sum of its proper divisors (37081).

131999999 is an equidigital number, since it uses as much as digits as its factorization.

131999999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37080.

The product of its digits is 1594323, while the sum is 59.

The square root of 131999999 is about 11489.1252495566. The cubic root of 131999999 is about 509.1643356802.

The spelling of 131999999 in words is "one hundred thirty-one million, nine hundred ninety-nine thousand, nine hundred ninety-nine".