210001211221 has 8 divisors (see below), whose sum is σ = 210227732120. Its totient is φ = 209774748672.

The previous prime is 210001211209. The next prime is 210001211237. The reversal of 210001211221 is 122112100012.

It can be written as a sum of positive squares in 4 ways, for example, as 36517299025 + 173483912196 = 191095^2 + 416514^2 .

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 210001211221 - 2¹³ = 210001203029 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 (210001211521) 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, 13924741 + ... + 13939813.

It is an arithmetic number, because the mean of its divisors is an integer number (26278466515).

Almost surely, 2^210001211221 is an apocalyptic number.

It is an amenable number.

210001211221 is a deficient number, since it is larger than the sum of its proper divisors (226520899).

210001211221 is a wasteful number, since it uses less digits than its factorization.

210001211221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29175.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 210001211221 its reverse (122112100012), we get a palindrome (332113311233).

The spelling of 210001211221 in words is "two hundred ten billion, one million, two hundred eleven thousand, two hundred twenty-one".