10000020001221 has 12 divisors (see below), whose sum is σ = 14444762431372. Its totient is φ = 6666546571776.

The previous prime is 10000020001201. The next prime is 10000020001261. The reversal of 10000020001221 is 12210002000001.

It can be written as a sum of positive squares in 2 ways, for example, as 5532440268996 + 4467579732225 = 2352114^2 + 2113665^2 .

It is not a de Polignac number, because 10000020001221 - 2⁵ = 10000020001189 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (10000020001201) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10643356 + ... + 11544741.

Almost surely, 2^{10000020001221} is an apocalyptic number.

It is an amenable number.

10000020001221 is a deficient number, since it is larger than the sum of its proper divisors (4444742430151).

10000020001221 is a wasteful number, since it uses less digits than its factorization.

10000020001221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22238180 (or 22238177 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 10000020001221 its reverse (12210002000001), we get a palindrome (22210022001222).

The spelling of 10000020001221 in words is "ten trillion, twenty million, one thousand, two hundred twenty-one".