161729569 has 4 divisors (see below), whose sum is σ = 162664596. Its totient is φ = 160794544.

The previous prime is 161729563. The next prime is 161729593. The reversal of 161729569 is 965927161.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 965927161 = 5189 ⋅186149.

It can be written as a sum of positive squares in 2 ways, for example, as 151585344 + 10144225 = 12312^2 + 3185^2 .

It is a cyclic number.

It is not a de Polignac number, because 161729569 - 2¹³ = 161721377 is a prime.

It is a super-2 number, since 2×161729569² = 52312906977851522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161729563) 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, 467254 + ... + 467599.

It is an arithmetic number, because the mean of its divisors is an integer number (40666149).

Almost surely, 2^161729569 is an apocalyptic number.

It is an amenable number.

161729569 is a deficient number, since it is larger than the sum of its proper divisors (935027).

161729569 is an equidigital number, since it uses as much as digits as its factorization.

161729569 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 935026.

The product of its digits is 204120, while the sum is 46.

The square root of 161729569 is about 12717.2940911186. The cubic root of 161729569 is about 544.8326720275.

The spelling of 161729569 in words is "one hundred sixty-one million, seven hundred twenty-nine thousand, five hundred sixty-nine".