210001220221 has 8 divisors (see below), whose sum is σ = 231671140344. Its totient is φ = 189119297280.

The previous prime is 210001220207. The next prime is 210001220227. The reversal of 210001220221 is 122022100012.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 32245384900 + 177755835321 = 179570^2 + 421611^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 210001220221 - 2²⁹ = 209464349309 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (210001220227) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 196998736 + ... + 196999801.

It is an arithmetic number, because the mean of its divisors is an integer number (28958892543).

Almost surely, 2^210001220221 is an apocalyptic number.

It is an amenable number.

210001220221 is a deficient number, since it is larger than the sum of its proper divisors (21669920123).

210001220221 is a wasteful number, since it uses less digits than its factorization.

210001220221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 393998591.

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 210001220221 its reverse (122022100012), we get a palindrome (332023320233).

The spelling of 210001220221 in words is "two hundred ten billion, one million, two hundred twenty thousand, two hundred twenty-one".