221001000221 has 4 divisors (see below), whose sum is σ = 221045445372. Its totient is φ = 220956555072.

The previous prime is 221001000203. The next prime is 221001000239. The reversal of 221001000221 is 122000100122.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 122000100122 = 2 ⋅61000050061.

It is an interprime number because it is at equal distance from previous prime (221001000203) and next prime (221001000239).

It can be written as a sum of positive squares in 2 ways, for example, as 49277784196 + 171723216025 = 221986^2 + 414395^2 .

It is a cyclic number.

It is not a de Polignac number, because 221001000221 - 2²⁶ = 220933891357 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 (221001000271) 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, 22215116 + ... + 22225061.

It is an arithmetic number, because the mean of its divisors is an integer number (55261361343).

Almost surely, 2^221001000221 is an apocalyptic number.

It is an amenable number.

221001000221 is a deficient number, since it is larger than the sum of its proper divisors (44445151).

221001000221 is an equidigital number, since it uses as much as digits as its factorization.

221001000221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44445150.

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 221001000221 its reverse (122000100122), we get a palindrome (343001100343).

Subtracting from 221001000221 its reverse (122000100122), we obtain a palindrome (99000900099).

The spelling of 221001000221 in words is "two hundred twenty-one billion, one million, two hundred twenty-one", and thus it is an aban number.