165990649 has 4 divisors (see below), whose sum is σ = 181080720. Its totient is φ = 150900580.

The previous prime is 165990611. The next prime is 165990661. The reversal of 165990649 is 946099561.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 165990649 - 2⁷ = 165990521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165990679) 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, 7545019 + ... + 7545040.

It is an arithmetic number, because the mean of its divisors is an integer number (45270180).

Almost surely, 2^165990649 is an apocalyptic number.

It is an amenable number.

165990649 is a deficient number, since it is larger than the sum of its proper divisors (15090071).

165990649 is a wasteful number, since it uses less digits than its factorization.

165990649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15090070.

The product of its (nonzero) digits is 524880, while the sum is 49.

The square root of 165990649 is about 12883.7358324362. The cubic root of 165990649 is about 549.5761461711.

The spelling of 165990649 in words is "one hundred sixty-five million, nine hundred ninety thousand, six hundred forty-nine".