1221012120221 has 2 divisors, whose sum is σ = 1221012120222. Its totient is φ = 1221012120220.

The previous prime is 1221012120203. The next prime is 1221012120233. The reversal of 1221012120221 is 1220212101221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1042134722500 + 178877397721 = 1020850^2 + 422939^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221012120221 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1221012120221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221012120271) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610506060110 + 610506060111.

It is an arithmetic number, because the mean of its divisors is an integer number (610506060111).

Almost surely, 2^{1221012120221} is an apocalyptic number.

It is an amenable number.

1221012120221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221012120221 is an equidigital number, since it uses as much as digits as its factorization.

1221012120221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 1221012120221 its reverse (1220212101221), we get a palindrome (2441224221442).

The spelling of 1221012120221 in words is "one trillion, two hundred twenty-one billion, twelve million, one hundred twenty thousand, two hundred twenty-one".