131223999 has 4 divisors (see below), whose sum is σ = 174965336. Its totient is φ = 87482664.

The previous prime is 131223991. The next prime is 131224007. The reversal of 131223999 is 999322131.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (131223991) and next prime (131224007).

It is not a de Polignac number, because 131223999 - 2³ = 131223991 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 (131223991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21870664 + ... + 21870669.

It is an arithmetic number, because the mean of its divisors is an integer number (43741334).

Almost surely, 2^131223999 is an apocalyptic number.

131223999 is a deficient number, since it is larger than the sum of its proper divisors (43741337).

131223999 is an equidigital number, since it uses as much as digits as its factorization.

131223999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43741336.

The product of its digits is 26244, while the sum is 39.

The square root of 131223999 is about 11455.3044045106. The cubic root of 131223999 is about 508.1646176875.

The spelling of 131223999 in words is "one hundred thirty-one million, two hundred twenty-three thousand, nine hundred ninety-nine".