161664559 has 16 divisors (see below), whose sum is σ = 197159680. Its totient is φ = 129470400.

The previous prime is 161664551. The next prime is 161664571. The reversal of 161664559 is 955466161.

It is a cyclic number.

It is not a de Polignac number, because 161664559 - 2³ = 161664551 is a prime.

It is a super-2 number, since 2×161664559² = 52270859273328962, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161664551) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1384 + ... + 18034.

It is an arithmetic number, because the mean of its divisors is an integer number (12322480).

Almost surely, 2^161664559 is an apocalyptic number.

161664559 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

161664559 is a deficient number, since it is larger than the sum of its proper divisors (35495121).

161664559 is a wasteful number, since it uses less digits than its factorization.

161664559 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16750.

The product of its digits is 194400, while the sum is 43.

The square root of 161664559 is about 12714.7378659570. The cubic root of 161664559 is about 544.7596606025.

The spelling of 161664559 in words is "one hundred sixty-one million, six hundred sixty-four thousand, five hundred fifty-nine".