921021001311221 has 2 divisors, whose sum is σ = 921021001311222. Its totient is φ = 921021001311220.

The previous prime is 921021001311199. The next prime is 921021001311329. The reversal of 921021001311221 is 122113100120129.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 634158558075025 + 286862443236196 = 25182505^2 + 16937014^2 .

It is an emirp because it is prime and its reverse (122113100120129) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 921021001311221 - 2¹⁰ = 921021001310197 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (921021001361221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 460510500655610 + 460510500655611.

It is an arithmetic number, because the mean of its divisors is an integer number (460510500655611).

Almost surely, 2^{921021001311221} is an apocalyptic number.

It is an amenable number.

921021001311221 is a deficient number, since it is larger than the sum of its proper divisors (1).

921021001311221 is an equidigital number, since it uses as much as digits as its factorization.

921021001311221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 432, while the sum is 26.

The spelling of 921021001311221 in words is "nine hundred twenty-one trillion, twenty-one billion, one million, three hundred eleven thousand, two hundred twenty-one".