221647231 has 16 divisors (see below), whose sum is σ = 243107424. Its totient is φ = 200853504.

The previous prime is 221647213. The next prime is 221647273. The reversal of 221647231 is 132746122.

It is a cyclic number.

It is not a de Polignac number, because 221647231 - 2¹¹ = 221645183 is a prime.

It is a super-2 number, since 2×221647231² = 98254990019934722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 221647231.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221677231) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 172116 + ... + 173398.

It is an arithmetic number, because the mean of its divisors is an integer number (15194214).

Almost surely, 2^221647231 is an apocalyptic number.

221647231 is a deficient number, since it is larger than the sum of its proper divisors (21460193).

221647231 is a wasteful number, since it uses less digits than its factorization.

221647231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1530.

The product of its digits is 4032, while the sum is 28.

The square root of 221647231 is about 14887.8215666363. The cubic root of 221647231 is about 605.1839988579.

The spelling of 221647231 in words is "two hundred twenty-one million, six hundred forty-seven thousand, two hundred thirty-one".