221645172 has 24 divisors (see below), whose sum is σ = 591054016. Its totient is φ = 63327168.

The previous prime is 221645143. The next prime is 221645183. The reversal of 221645172 is 271546122.

It is a congruent number.

It is an unprimeable number.

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, 1319233 + ... + 1319400.

Almost surely, 2^221645172 is an apocalyptic number.

It is an amenable number.

221645172 is an abundant number, since it is smaller than the sum of its proper divisors (369408844).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

221645172 is a wasteful number, since it uses less digits than its factorization.

221645172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2638647 (or 2638645 counting only the distinct ones).

The product of its digits is 6720, while the sum is 30.

The square root of 221645172 is about 14887.7524159962. The cubic root of 221645172 is about 605.1821248925.

The spelling of 221645172 in words is "two hundred twenty-one million, six hundred forty-five thousand, one hundred seventy-two".