1243020309989 has 2 divisors, whose sum is σ = 1243020309990. Its totient is φ = 1243020309988.

The previous prime is 1243020309929. The next prime is 1243020310057. The reversal of 1243020309989 is 9899030203421.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1177967256964 + 65053053025 = 1085342^2 + 255055^2 .

It is an emirp because it is prime and its reverse (9899030203421) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1243020309989 - 2²⁰ = 1243019261413 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1243020309919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 621510154994 + 621510154995.

It is an arithmetic number, because the mean of its divisors is an integer number (621510154995).

Almost surely, 2^{1243020309989} is an apocalyptic number.

It is an amenable number.

1243020309989 is a deficient number, since it is larger than the sum of its proper divisors (1).

1243020309989 is an equidigital number, since it uses as much as digits as its factorization.

1243020309989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 839808, while the sum is 50.

The spelling of 1243020309989 in words is "one trillion, two hundred forty-three billion, twenty million, three hundred nine thousand, nine hundred eighty-nine".