21212320220921 has 2 divisors, whose sum is σ = 21212320220922. Its totient is φ = 21212320220920.

The previous prime is 21212320220813. The next prime is 21212320221013. The reversal of 21212320220921 is 12902202321212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10764304810000 + 10448015410921 = 3280900^2 + 3232339^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21212320220921 is a prime.

It is not a weakly prime, because it can be changed into another prime (21212320222921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606160110460 + 10606160110461.

It is an arithmetic number, because the mean of its divisors is an integer number (10606160110461).

Almost surely, 2^{21212320220921} is an apocalyptic number.

It is an amenable number.

21212320220921 is a deficient number, since it is larger than the sum of its proper divisors (1).

21212320220921 is an equidigital number, since it uses as much as digits as its factorization.

21212320220921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3456, while the sum is 29.

The spelling of 21212320220921 in words is "twenty-one trillion, two hundred twelve billion, three hundred twenty million, two hundred twenty thousand, nine hundred twenty-one".