1221552543073 has 2 divisors, whose sum is σ = 1221552543074. Its totient is φ = 1221552543072.

The previous prime is 1221552543037. The next prime is 1221552543083. The reversal of 1221552543073 is 3703452551221.

Together with previous prime (1221552543037) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1215689271889 + 5863271184 = 1102583^2 + 76572^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221552543073 is a prime.

It is a super-2 number, since 2×1221552543073² (a number of 25 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1221552543083) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610776271536 + 610776271537.

It is an arithmetic number, because the mean of its divisors is an integer number (610776271537).

Almost surely, 2^{1221552543073} is an apocalyptic number.

It is an amenable number.

1221552543073 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221552543073 is an equidigital number, since it uses as much as digits as its factorization.

1221552543073 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 252000, while the sum is 40.

The spelling of 1221552543073 in words is "one trillion, two hundred twenty-one billion, five hundred fifty-two million, five hundred forty-three thousand, seventy-three".