165998305 has 16 divisors (see below), whose sum is σ = 217603584. Its totient is φ = 120561280.

The previous prime is 165998303. The next prime is 165998309. The reversal of 165998305 is 503899561.

It is not a de Polignac number, because 165998305 - 2¹ = 165998303 is a prime.

It is not an unprimeable number, because it can be changed into a prime (165998303) 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, 50832 + ... + 53998.

It is an arithmetic number, because the mean of its divisors is an integer number (13600224).

Almost surely, 2^165998305 is an apocalyptic number.

It is an amenable number.

165998305 is a deficient number, since it is larger than the sum of its proper divisors (51605279).

165998305 is a wasteful number, since it uses less digits than its factorization.

165998305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4136.

The product of its (nonzero) digits is 291600, while the sum is 46.

The square root of 165998305 is about 12884.0329478002. The cubic root of 165998305 is about 549.5845954227.

It can be divided in two parts, 165 and 998305, that multiplied together give a triangular number (164720325 = T₁₈₁₅₀).

The spelling of 165998305 in words is "one hundred sixty-five million, nine hundred ninety-eight thousand, three hundred five".