165501999 has 24 divisors (see below), whose sum is σ = 264412512. Its totient is φ = 99092160.

The previous prime is 165501991. The next prime is 165502009. The reversal of 165501999 is 999105561.

It is a happy number.

165501999 is a `hidden beast` number, since 1 + 6 + 550 + 1 + 9 + 99 = 666.

It is not a de Polignac number, because 165501999 - 2³ = 165501991 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165501991) 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 23 ways as a sum of consecutive naturals, for example, 14787 + ... + 23444.

It is an arithmetic number, because the mean of its divisors is an integer number (11017188).

Almost surely, 2^165501999 is an apocalyptic number.

165501999 is a deficient number, since it is larger than the sum of its proper divisors (98910513).

165501999 is a wasteful number, since it uses less digits than its factorization.

165501999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38287 (or 38284 counting only the distinct ones).

The product of its (nonzero) digits is 109350, while the sum is 45.

The square root of 165501999 is about 12864.7580233753. The cubic root of 165501999 is about 549.0363279334.

The spelling of 165501999 in words is "one hundred sixty-five million, five hundred one thousand, nine hundred ninety-nine".