221997172 has 12 divisors (see below), whose sum is σ = 388627876. Its totient is φ = 110960640.

The previous prime is 221997157. The next prime is 221997179. The reversal of 221997172 is 271799122.

It can be written as a sum of positive squares in 2 ways, for example, as 59536656 + 162460516 = 7716^2 + 12746^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221997179) 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, 6772 + ... + 22132.

Almost surely, 2^221997172 is an apocalyptic number.

It is an amenable number.

221997172 is a deficient number, since it is larger than the sum of its proper divisors (166630704).

221997172 is a wasteful number, since it uses less digits than its factorization.

221997172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18978 (or 18976 counting only the distinct ones).

The product of its digits is 31752, while the sum is 40.

The square root of 221997172 is about 14899.5695239829. The cubic root of 221997172 is about 605.5023235173.

The spelling of 221997172 in words is "two hundred twenty-one million, nine hundred ninety-seven thousand, one hundred seventy-two".