1221021121589 has 2 divisors, whose sum is σ = 1221021121590. Its totient is φ = 1221021121588.

The previous prime is 1221021121577. The next prime is 1221021121601. The reversal of 1221021121589 is 9851211201221.

It is a balanced prime because it is at equal distance from previous prime (1221021121577) and next prime (1221021121601).

It can be written as a sum of positive squares in only one way, i.e., 975245127025 + 245775994564 = 987545^2 + 495758^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221021121589 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221021121559) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610510560794 + 610510560795.

It is an arithmetic number, because the mean of its divisors is an integer number (610510560795).

Almost surely, 2^{1221021121589} is an apocalyptic number.

It is an amenable number.

1221021121589 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221021121589 is an equidigital number, since it uses as much as digits as its factorization.

1221021121589 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5760, while the sum is 35.

The spelling of 1221021121589 in words is "one trillion, two hundred twenty-one billion, twenty-one million, one hundred twenty-one thousand, five hundred eighty-nine".