1221011017913 has 2 divisors, whose sum is σ = 1221011017914. Its totient is φ = 1221011017912.

The previous prime is 1221011017901. The next prime is 1221011017927. The reversal of 1221011017913 is 3197101101221.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1103693122624 + 117317895289 = 1050568^2 + 342517^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221011017913 - 2²⁶ = 1220943909049 is a prime.

It is not a weakly prime, because it can be changed into another prime (1221011017973) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610505508956 + 610505508957.

It is an arithmetic number, because the mean of its divisors is an integer number (610505508957).

Almost surely, 2^{1221011017913} is an apocalyptic number.

It is an amenable number.

1221011017913 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221011017913 is an equidigital number, since it uses as much as digits as its factorization.

1221011017913 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 756, while the sum is 29.

The spelling of 1221011017913 in words is "one trillion, two hundred twenty-one billion, eleven million, seventeen thousand, nine hundred thirteen".