221220231 has 4 divisors (see below), whose sum is σ = 294960312. Its totient is φ = 147480152.

The previous prime is 221220229. The next prime is 221220257. The reversal of 221220231 is 132022122.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 221220231 - 2¹ = 221220229 is a prime.

It is a super-2 number, since 2×221220231² = 97876781207386722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 221220231.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221220331) 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, 36870036 + ... + 36870041.

It is an arithmetic number, because the mean of its divisors is an integer number (73740078).

Almost surely, 2^221220231 is an apocalyptic number.

221220231 is a deficient number, since it is larger than the sum of its proper divisors (73740081).

221220231 is an equidigital number, since it uses as much as digits as its factorization.

221220231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73740080.

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 221220231 is about 14873.4740729932. The cubic root of 221220231 is about 604.7951231244.

Adding to 221220231 its reverse (132022122), we get a palindrome (353242353).

The spelling of 221220231 in words is "two hundred twenty-one million, two hundred twenty thousand, two hundred thirty-one".