166616661 has 32 divisors (see below), whose sum is σ = 241468416. Its totient is φ = 101952000.

The previous prime is 166616657. The next prime is 166616663.

It is a happy number.

166616661 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 166616661 - 2² = 166616657 is a prime.

It is a super-2 number, since 2×166616661² = 55522223445577842, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166616663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 140491 + ... + 141671.

It is an arithmetic number, because the mean of its divisors is an integer number (7545888).

Almost surely, 2^166616661 is an apocalyptic number.

It is an amenable number.

166616661 is a deficient number, since it is larger than the sum of its proper divisors (74851755).

166616661 is a wasteful number, since it uses less digits than its factorization.

166616661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1293.

The product of its digits is 46656, while the sum is 39.

The square root of 166616661 is about 12908.0076309243. The cubic root of 166616661 is about 550.2661642859.

The spelling of 166616661 in words is "one hundred sixty-six million, six hundred sixteen thousand, six hundred sixty-one".