166818381 has 8 divisors (see below), whose sum is σ = 227849664. Its totient is φ = 108499680.

The previous prime is 166818361. The next prime is 166818391. The reversal of 166818381 is 183818661.

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

It is not a de Polignac number, because 166818381 - 2⁵ = 166818349 is a prime.

It is a super-2 number, since 2×166818381² = 55656744478922322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166818361) 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, 678001 + ... + 678246.

It is an arithmetic number, because the mean of its divisors is an integer number (28481208).

Almost surely, 2^166818381 is an apocalyptic number.

It is an amenable number.

166818381 is a deficient number, since it is larger than the sum of its proper divisors (61031283).

166818381 is a wasteful number, since it uses less digits than its factorization.

166818381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1356291.

The product of its digits is 55296, while the sum is 42.

The square root of 166818381 is about 12915.8190216494. The cubic root of 166818381 is about 550.4881407376.

The spelling of 166818381 in words is "one hundred sixty-six million, eight hundred eighteen thousand, three hundred eighty-one".