21033313101221 has 2 divisors, whose sum is σ = 21033313101222. Its totient is φ = 21033313101220.

The previous prime is 21033313101211. The next prime is 21033313101257. The reversal of 21033313101221 is 12210131333012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11386480876996 + 9646832224225 = 3374386^2 + 3105935^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21033313101221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21033313101211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10516656550610 + 10516656550611.

It is an arithmetic number, because the mean of its divisors is an integer number (10516656550611).

Almost surely, 2^{21033313101221} is an apocalyptic number.

It is an amenable number.

21033313101221 is a deficient number, since it is larger than the sum of its proper divisors (1).

21033313101221 is an equidigital number, since it uses as much as digits as its factorization.

21033313101221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 648, while the sum is 23.

Adding to 21033313101221 its reverse (12210131333012), we get a palindrome (33243444434233).

The spelling of 21033313101221 in words is "twenty-one trillion, thirty-three billion, three hundred thirteen million, one hundred one thousand, two hundred twenty-one".