166181998 has 4 divisors (see below), whose sum is σ = 249273000. Its totient is φ = 83090998.

The previous prime is 166181947. The next prime is 166182001. The reversal of 166181998 is 899181661.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41545498 + ... + 41545501.

It is an arithmetic number, because the mean of its divisors is an integer number (62318250).

Almost surely, 2^166181998 is an apocalyptic number.

166181998 is a deficient number, since it is larger than the sum of its proper divisors (83091002).

166181998 is an equidigital number, since it uses as much as digits as its factorization.

166181998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83091001.

The product of its digits is 186624, while the sum is 49.

The square root of 166181998 is about 12891.1596840626. The cubic root of 166181998 is about 549.7872433297.

The spelling of 166181998 in words is "one hundred sixty-six million, one hundred eighty-one thousand, nine hundred ninety-eight".