166421855 has 16 divisors (see below), whose sum is σ = 214189920. Its totient is φ = 123746688.

The previous prime is 166421851. The next prime is 166421861. The reversal of 166421855 is 558124661.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 166421855 - 2² = 166421851 is a prime.

It is a super-3 number, since 3×166421855³ (a number of 26 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166421851) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11492 + ... + 21561.

It is an arithmetic number, because the mean of its divisors is an integer number (13386870).

Almost surely, 2^166421855 is an apocalyptic number.

166421855 is a deficient number, since it is larger than the sum of its proper divisors (47768065).

166421855 is a wasteful number, since it uses less digits than its factorization.

166421855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33130.

The product of its digits is 57600, while the sum is 38.

The square root of 166421855 is about 12900.4594879407. The cubic root of 166421855 is about 550.0516260079.

The spelling of 166421855 in words is "one hundred sixty-six million, four hundred twenty-one thousand, eight hundred fifty-five".