165819899 has 16 divisors (see below), whose sum is σ = 198844416. Its totient is φ = 135280800.

The previous prime is 165819893. The next prime is 165819919. The reversal of 165819899 is 998918561.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-165819899 is a prime.

It is not an unprimeable number, because it can be changed into a prime (165819893) 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 15 ways as a sum of consecutive naturals, for example, 6974 + ... + 19500.

It is an arithmetic number, because the mean of its divisors is an integer number (12427776).

Almost surely, 2^165819899 is an apocalyptic number.

165819899 is a deficient number, since it is larger than the sum of its proper divisors (33024517).

165819899 is a wasteful number, since it uses less digits than its factorization.

165819899 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12626.

The product of its digits is 1399680, while the sum is 56.

The square root of 165819899 is about 12877.1075556586. The cubic root of 165819899 is about 549.3876369130.

The spelling of 165819899 in words is "one hundred sixty-five million, eight hundred nineteen thousand, eight hundred ninety-nine".