166321661 has 8 divisors (see below), whose sum is σ = 182828448. Its totient is φ = 150046000.

The previous prime is 166321637. The next prime is 166321679. The reversal of 166321661 is 166123661.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166321661 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166321601) 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, 56270 + ... + 59151.

It is an arithmetic number, because the mean of its divisors is an integer number (22853556).

Almost surely, 2^166321661 is an apocalyptic number.

166321661 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

166321661 is a deficient number, since it is larger than the sum of its proper divisors (16506787).

166321661 is a wasteful number, since it uses less digits than its factorization.

166321661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 115563.

The product of its digits is 7776, while the sum is 32.

The square root of 166321661 is about 12896.5755532234. The cubic root of 166321661 is about 549.9412179602.

The spelling of 166321661 in words is "one hundred sixty-six million, three hundred twenty-one thousand, six hundred sixty-one".