165561497 has 4 divisors (see below), whose sum is σ = 174275280. Its totient is φ = 156847716.

The previous prime is 165561491. The next prime is 165561541. The reversal of 165561497 is 794165561.

165561497 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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, and also an emirpimes, since its reverse is a distinct semiprime: 794165561 = 7 ⋅113452223.

It is a cyclic number.

It is not a de Polignac number, because 165561497 - 2¹² = 165557401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165561491) 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, 4356863 + ... + 4356900.

It is an arithmetic number, because the mean of its divisors is an integer number (43568820).

Almost surely, 2^165561497 is an apocalyptic number.

It is an amenable number.

165561497 is a deficient number, since it is larger than the sum of its proper divisors (8713783).

165561497 is an equidigital number, since it uses as much as digits as its factorization.

165561497 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8713782.

The product of its digits is 226800, while the sum is 44.

The square root of 165561497 is about 12867.0702570554. The cubic root of 165561497 is about 549.1021129388.

The spelling of 165561497 in words is "one hundred sixty-five million, five hundred sixty-one thousand, four hundred ninety-seven".