221654221 has 4 divisors (see below), whose sum is σ = 229297500. Its totient is φ = 214010944.

The previous prime is 221654219. The next prime is 221654273. The reversal of 221654221 is 122456122.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 122456122 = 2 ⋅61228061.

It can be written as a sum of positive squares in 2 ways, for example, as 86769225 + 134884996 = 9315^2 + 11614^2 .

It is a cyclic number.

It is not a de Polignac number, because 221654221 - 2¹ = 221654219 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221654201) 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, 3821596 + ... + 3821653.

It is an arithmetic number, because the mean of its divisors is an integer number (57324375).

Almost surely, 2^221654221 is an apocalyptic number.

It is an amenable number.

221654221 is a deficient number, since it is larger than the sum of its proper divisors (7643279).

221654221 is an equidigital number, since it uses as much as digits as its factorization.

221654221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7643278.

The product of its digits is 1920, while the sum is 25.

The square root of 221654221 is about 14888.0563204201. The cubic root of 221654221 is about 605.1903606062.

The spelling of 221654221 in words is "two hundred twenty-one million, six hundred fifty-four thousand, two hundred twenty-one".