168551221 has 4 divisors (see below), whose sum is σ = 168660352. Its totient is φ = 168442092.

The previous prime is 168551203. The next prime is 168551267. The reversal of 168551221 is 122155861.

168551221 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 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 168551221 - 2⁵ = 168551189 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 (168551921) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 52215 + ... + 55348.

It is an arithmetic number, because the mean of its divisors is an integer number (42165088).

Almost surely, 2^168551221 is an apocalyptic number.

It is an amenable number.

168551221 is a deficient number, since it is larger than the sum of its proper divisors (109131).

168551221 is a wasteful number, since it uses less digits than its factorization.

168551221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109130.

The product of its digits is 4800, while the sum is 31.

The square root of 168551221 is about 12982.7277950360. The cubic root of 168551221 is about 552.3876593661.

The spelling of 168551221 in words is "one hundred sixty-eight million, five hundred fifty-one thousand, two hundred twenty-one".