168021866 has 4 divisors (see below), whose sum is σ = 252032802. Its totient is φ = 84010932.

The previous prime is 168021859. The next prime is 168021881. The reversal of 168021866 is 668120861.

168021866 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 668120861 = 61 ⋅10952801.

It can be written as a sum of positive squares in only one way, i.e., 124791241 + 43230625 = 11171^2 + 6575^2 .

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42005465 + ... + 42005468.

Almost surely, 2^168021866 is an apocalyptic number.

168021866 is a deficient number, since it is larger than the sum of its proper divisors (84010936).

168021866 is an equidigital number, since it uses as much as digits as its factorization.

168021866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84010935.

The product of its (nonzero) digits is 27648, while the sum is 38.

The square root of 168021866 is about 12962.3248686337. The cubic root of 168021866 is about 551.8087733790.

The spelling of 168021866 in words is "one hundred sixty-eight million, twenty-one thousand, eight hundred sixty-six".