165909473 has 4 divisors (see below), whose sum is σ = 165948180. Its totient is φ = 165870768.

The previous prime is 165909421. The next prime is 165909521. The reversal of 165909473 is 374909561.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 129572689 + 36336784 = 11383^2 + 6028^2 .

It is a cyclic number.

It is not a de Polignac number, because 165909473 - 2¹⁸ = 165647329 is a prime.

It is a super-2 number, since 2×165909473² = 55051906462275458, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165909173) 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, 11990 + ... + 21807.

It is an arithmetic number, because the mean of its divisors is an integer number (41487045).

Almost surely, 2^165909473 is an apocalyptic number.

It is an amenable number.

165909473 is a deficient number, since it is larger than the sum of its proper divisors (38707).

165909473 is an equidigital number, since it uses as much as digits as its factorization.

165909473 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38706.

The product of its (nonzero) digits is 204120, while the sum is 44.

The square root of 165909473 is about 12880.5851186971. The cubic root of 165909473 is about 549.4865433975.

The spelling of 165909473 in words is "one hundred sixty-five million, nine hundred nine thousand, four hundred seventy-three".