16131999 has 16 divisors (see below), whose sum is σ = 23547104. Its totient is φ = 9763200.

The previous prime is 16131989. The next prime is 16132019. The reversal of 16131999 is 99913161.

It is a happy number.

It is not a de Polignac number, because 16131999 - 2¹⁵ = 16099231 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16131949) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1012 + ... + 5769.

It is an arithmetic number, because the mean of its divisors is an integer number (1471694).

Almost surely, 2^16131999 is an apocalyptic number.

16131999 is a deficient number, since it is larger than the sum of its proper divisors (7415105).

16131999 is a wasteful number, since it uses less digits than its factorization.

16131999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6858.

The product of its digits is 13122, while the sum is 39.

The square root of 16131999 is about 4016.4659839217. The cubic root of 16131999 is about 252.6752643912.

The spelling of 16131999 in words is "sixteen million, one hundred thirty-one thousand, nine hundred ninety-nine".