1021012001221 has 2 divisors, whose sum is σ = 1021012001222. Its totient is φ = 1021012001220.

The previous prime is 1021012001183. The next prime is 1021012001227. The reversal of 1021012001221 is 1221002101201.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 921004896100 + 100007105121 = 959690^2 + 316239^2 .

It is an emirp because it is prime and its reverse (1221002101201) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1021012001221 - 2⁹ = 1021012000709 is a prime.

It is a super-2 number, since 2×1021012001221² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1021012001227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 510506000610 + 510506000611.

It is an arithmetic number, because the mean of its divisors is an integer number (510506000611).

Almost surely, 2^{1021012001221} is an apocalyptic number.

It is an amenable number.

1021012001221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1021012001221 is an equidigital number, since it uses as much as digits as its factorization.

1021012001221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 1021012001221 its reverse (1221002101201), we get a palindrome (2242014102422).

The spelling of 1021012001221 in words is "one trillion, twenty-one billion, twelve million, one thousand, two hundred twenty-one".