221746231 has 4 divisors (see below), whose sum is σ = 253424272. Its totient is φ = 190068192.

The previous prime is 221746229. The next prime is 221746253. The reversal of 221746231 is 132647122.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 132647122 = 2 ⋅66323561.

It is a cyclic number.

It is not a de Polignac number, because 221746231 - 2¹ = 221746229 is a prime.

It is a super-2 number, since 2×221746231² = 98342781925410722, 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 221746231.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221746271) 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, 15839010 + ... + 15839023.

It is an arithmetic number, because the mean of its divisors is an integer number (63356068).

Almost surely, 2^221746231 is an apocalyptic number.

221746231 is a deficient number, since it is larger than the sum of its proper divisors (31678041).

221746231 is an equidigital number, since it uses as much as digits as its factorization.

221746231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31678040.

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

The square root of 221746231 is about 14891.1460606630. The cubic root of 221746231 is about 605.2740884079.

The spelling of 221746231 in words is "two hundred twenty-one million, seven hundred forty-six thousand, two hundred thirty-one".