161669 has 4 divisors (see below), whose sum is σ = 162540. Its totient is φ = 160800.

The previous prime is 161659. The next prime is 161683. The reversal of 161669 is 966161.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 68644 + 93025 = 262^2 + 305^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161669 is a prime.

It is a super-2 number, since 2×161669² = 52273731122, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161639) 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, 32 + ... + 569.

It is an arithmetic number, because the mean of its divisors is an integer number (40635).

2¹⁶¹⁶⁶⁹ is an apocalyptic number.

It is an amenable number.

161669 is a deficient number, since it is larger than the sum of its proper divisors (871).

161669 is an equidigital number, since it uses as much as digits as its factorization.

161669 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 870.

The product of its digits is 1944, while the sum is 29.

The square root of 161669 is about 402.0808376434. The cubic root of 161669 is about 54.4764648823.

The spelling of 161669 in words is "one hundred sixty-one thousand, six hundred sixty-nine".