165945517 has 4 divisors (see below), whose sum is σ = 175707036. Its totient is φ = 156184000.

The previous prime is 165945509. The next prime is 165945539. The reversal of 165945517 is 715549561.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 715549561 = 113 ⋅6332297.

It can be written as a sum of positive squares in 2 ways, for example, as 147403881 + 18541636 = 12141^2 + 4306^2 .

It is a cyclic number.

It is not a de Polignac number, because 165945517 - 2³ = 165945509 is a prime.

It is a super-2 number, since 2×165945517² = 55075829224794578, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165945547) 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, 4880734 + ... + 4880767.

It is an arithmetic number, because the mean of its divisors is an integer number (43926759).

Almost surely, 2^165945517 is an apocalyptic number.

165945517 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

165945517 is a deficient number, since it is larger than the sum of its proper divisors (9761519).

165945517 is an equidigital number, since it uses as much as digits as its factorization.

165945517 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9761518.

The product of its digits is 189000, while the sum is 43.

The square root of 165945517 is about 12881.9842027539. The cubic root of 165945517 is about 549.5263326844.

The spelling of 165945517 in words is "one hundred sixty-five million, nine hundred forty-five thousand, five hundred seventeen".