165672945 has 20 divisors (see below), whose sum is σ = 296984820. Its totient is φ = 88358688.

The previous prime is 165672929. The next prime is 165672953. The reversal of 165672945 is 549276561.

It can be written as a sum of positive squares in 2 ways, for example, as 122744241 + 42928704 = 11079^2 + 6552^2 .

It is not a de Polignac number, because 165672945 - 2⁴ = 165672929 is a prime.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an alternating number because its digits alternate between odd and even.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 165672945.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 204130 + ... + 204939.

It is an arithmetic number, because the mean of its divisors is an integer number (14849241).

Almost surely, 2^165672945 is an apocalyptic number.

165672945 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

165672945 is a deficient number, since it is larger than the sum of its proper divisors (131311875).

165672945 is an equidigital number, since it uses as much as digits as its factorization.

165672945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 409086 (or 409077 counting only the distinct ones).

The product of its digits is 453600, while the sum is 45.

The square root of 165672945 is about 12871.4002734745. The cubic root of 165672945 is about 549.2252949730.

The spelling of 165672945 in words is "one hundred sixty-five million, six hundred seventy-two thousand, nine hundred forty-five".