168920221 has 4 divisors (see below), whose sum is σ = 169012000. Its totient is φ = 168828444.

The previous prime is 168920161. The next prime is 168920237. The reversal of 168920221 is 122029861.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 168920221 - 2⁷ = 168920093 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (168920821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 43071 + ... + 46828.

It is an arithmetic number, because the mean of its divisors is an integer number (42253000).

Almost surely, 2^168920221 is an apocalyptic number.

It is an amenable number.

168920221 is a deficient number, since it is larger than the sum of its proper divisors (91779).

168920221 is an equidigital number, since it uses as much as digits as its factorization.

168920221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91778.

The product of its (nonzero) digits is 3456, while the sum is 31.

The square root of 168920221 is about 12996.9312147137. The cubic root of 168920221 is about 552.7904696223.

The spelling of 168920221 in words is "one hundred sixty-eight million, nine hundred twenty thousand, two hundred twenty-one".