165239999 has 4 divisors (see below), whose sum is σ = 170937960. Its totient is φ = 159542040.

The previous prime is 165239989. The next prime is 165240029. The reversal of 165239999 is 999932561.

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 165239999 - 2¹⁶ = 165174463 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 165239999.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165239909) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2848937 + ... + 2848994.

It is an arithmetic number, because the mean of its divisors is an integer number (42734490).

Almost surely, 2^165239999 is an apocalyptic number.

165239999 is a deficient number, since it is larger than the sum of its proper divisors (5697961).

165239999 is an equidigital number, since it uses as much as digits as its factorization.

165239999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5697960.

The product of its digits is 1180980, while the sum is 53.

The square root of 165239999 is about 12854.5711324805. The cubic root of 165239999 is about 548.7464553193.

The spelling of 165239999 in words is "one hundred sixty-five million, two hundred thirty-nine thousand, nine hundred ninety-nine".