22121221000721 has 2 divisors, whose sum is σ = 22121221000722. Its totient is φ = 22121221000720.

The previous prime is 22121221000699. The next prime is 22121221000763. The reversal of 22121221000721 is 12700012212122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15651518440000 + 6469702560721 = 3956200^2 + 2543561^2 .

It is a cyclic number.

It is not a de Polignac number, because 22121221000721 - 2³⁰ = 22120147258897 is a prime.

It is not a weakly prime, because it can be changed into another prime (22121221090721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11060610500360 + 11060610500361.

It is an arithmetic number, because the mean of its divisors is an integer number (11060610500361).

Almost surely, 2^{22121221000721} is an apocalyptic number.

It is an amenable number.

22121221000721 is a deficient number, since it is larger than the sum of its proper divisors (1).

22121221000721 is an equidigital number, since it uses as much as digits as its factorization.

22121221000721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 448, while the sum is 23.

Adding to 22121221000721 its reverse (12700012212122), we get a palindrome (34821233212843).

The spelling of 22121221000721 in words is "twenty-two trillion, one hundred twenty-one billion, two hundred twenty-one million, seven hundred twenty-one", and thus it is an aban number.