166027681 has 4 divisors (see below), whose sum is σ = 174766000. Its totient is φ = 157289364.

The previous prime is 166027679. The next prime is 166027709. The reversal of 166027681 is 186720661.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 186720661 = 7741 ⋅24121.

It is a cyclic number.

It is not a de Polignac number, because 166027681 - 2¹ = 166027679 is a prime.

It is a super-2 number, since 2×166027681² = 55130381716475522, 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 166027681.

It is not an unprimeable number, because it can be changed into a prime (166027651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4369131 + ... + 4369168.

It is an arithmetic number, because the mean of its divisors is an integer number (43691500).

Almost surely, 2^166027681 is an apocalyptic number.

It is an amenable number.

166027681 is a deficient number, since it is larger than the sum of its proper divisors (8738319).

166027681 is an equidigital number, since it uses as much as digits as its factorization.

166027681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8738318.

The product of its (nonzero) digits is 24192, while the sum is 37.

The square root of 166027681 is about 12885.1729130811. The cubic root of 166027681 is about 549.6170127112.

The spelling of 166027681 in words is "one hundred sixty-six million, twenty-seven thousand, six hundred eighty-one".