161664661 has 8 divisors (see below), whose sum is σ = 166390560. Its totient is φ = 157005072.

The previous prime is 161664653. The next prime is 161664667. The reversal of 161664661 is 166466161.

161664661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 161664661 - 2³ = 161664653 is a prime.

It is a super-2 number, since 2×161664661² = 52270925232489842, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 161664661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161664667) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11610 + ... + 21403.

It is an arithmetic number, because the mean of its divisors is an integer number (20798820).

Almost surely, 2^161664661 is an apocalyptic number.

It is an amenable number.

161664661 is a deficient number, since it is larger than the sum of its proper divisors (4725899).

161664661 is an equidigital number, since it uses as much as digits as its factorization.

161664661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33155.

The product of its digits is 31104, while the sum is 37.

The square root of 161664661 is about 12714.7418770496. The cubic root of 161664661 is about 544.7597751719.

The spelling of 161664661 in words is "one hundred sixty-one million, six hundred sixty-four thousand, six hundred sixty-one".