166171561 has 8 divisors (see below), whose sum is σ = 168414624. Its totient is φ = 163934400.

The previous prime is 166171559. The next prime is 166171609. The reversal of 166171561 is 165171661.

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 166171561 - 2¹ = 166171559 is a prime.

It is a super-2 number, since 2×166171561² = 55225975370353442, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166171531) 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, 98850 + ... + 100516.

It is an arithmetic number, because the mean of its divisors is an integer number (21051828).

Almost surely, 2^166171561 is an apocalyptic number.

It is an amenable number.

166171561 is a deficient number, since it is larger than the sum of its proper divisors (2243063).

166171561 is a wasteful number, since it uses less digits than its factorization.

166171561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2951.

The product of its digits is 7560, while the sum is 34.

The square root of 166171561 is about 12890.7548654064. The cubic root of 166171561 is about 549.7757333594.

The spelling of 166171561 in words is "one hundred sixty-six million, one hundred seventy-one thousand, five hundred sixty-one".