166809905 has 8 divisors (see below), whose sum is σ = 200696832. Its totient is φ = 133097968.

The previous prime is 166809901. The next prime is 166809913. The reversal of 166809905 is 509908661.

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 166809905 - 2² = 166809901 is a prime.

It is a super-2 number, since 2×166809905² = 55651088812218050, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166809901) 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 7 ways as a sum of consecutive naturals, for example, 41639 + ... + 45468.

It is an arithmetic number, because the mean of its divisors is an integer number (25087104).

Almost surely, 2^166809905 is an apocalyptic number.

It is an amenable number.

166809905 is a deficient number, since it is larger than the sum of its proper divisors (33886927).

166809905 is an equidigital number, since it uses as much as digits as its factorization.

166809905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87495.

The product of its (nonzero) digits is 116640, while the sum is 44.

The square root of 166809905 is about 12915.4908927226. The cubic root of 166809905 is about 550.4788171917.

The spelling of 166809905 in words is "one hundred sixty-six million, eight hundred nine thousand, nine hundred five".