166120681 has 8 divisors (see below), whose sum is σ = 167355720. Its totient is φ = 164890752.

The previous prime is 166120663. The next prime is 166120693. The reversal of 166120681 is 186021661.

It can be written as a sum of positive squares in 4 ways, for example, as 22240656 + 143880025 = 4716^2 + 11995^2 .

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 166120681 - 2⁵ = 166120649 is a prime.

It is a super-2 number, since 2×166120681² = 55192161311807522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166120621) 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, 83211 + ... + 85183.

It is an arithmetic number, because the mean of its divisors is an integer number (20919465).

Almost surely, 2^166120681 is an apocalyptic number.

It is an amenable number.

166120681 is a deficient number, since it is larger than the sum of its proper divisors (1235039).

166120681 is a wasteful number, since it uses less digits than its factorization.

166120681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2555.

The product of its (nonzero) digits is 3456, while the sum is 31.

The square root of 166120681 is about 12888.7812069257. The cubic root of 166120681 is about 549.7196157650.

The spelling of 166120681 in words is "one hundred sixty-six million, one hundred twenty thousand, six hundred eighty-one".