10000021221 has 12 divisors (see below), whose sum is σ = 14606773740. Its totient is φ = 6591773760.

The previous prime is 10000021217. The next prime is 10000021249. The reversal of 10000021221 is 12212000001.

It can be written as a sum of positive squares in 2 ways, for example, as 4136290596 + 5863730625 = 64314^2 + 76575^2 .

It is not a de Polignac number, because 10000021221 - 2² = 10000021217 is a prime.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (10000021321) 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, 6241410 + ... + 6243011.

It is an arithmetic number, because the mean of its divisors is an integer number (1217231145).

Almost surely, 2^10000021221 is an apocalyptic number.

It is an amenable number.

10000021221 is a deficient number, since it is larger than the sum of its proper divisors (4606752519).

10000021221 is a wasteful number, since it uses less digits than its factorization.

10000021221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12484516 (or 12484513 counting only the distinct ones).

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

Adding to 10000021221 its reverse (12212000001), we get a palindrome (22212021222).

The spelling of 10000021221 in words is "ten billion, twenty-one thousand, two hundred twenty-one".