1209391191913 has 2 divisors, whose sum is σ = 1209391191914. Its totient is φ = 1209391191912.

The previous prime is 1209391191839. The next prime is 1209391191919. The reversal of 1209391191913 is 3191911939021.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1106384215104 + 103006976809 = 1051848^2 + 320947^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1209391191913 is a prime.

It is not a weakly prime, because it can be changed into another prime (1209391191919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 604695595956 + 604695595957.

It is an arithmetic number, because the mean of its divisors is an integer number (604695595957).

Almost surely, 2^{1209391191913} is an apocalyptic number.

It is an amenable number.

1209391191913 is a deficient number, since it is larger than the sum of its proper divisors (1).

1209391191913 is an equidigital number, since it uses as much as digits as its factorization.

1209391191913 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 118098, while the sum is 49.

The spelling of 1209391191913 in words is "one trillion, two hundred nine billion, three hundred ninety-one million, one hundred ninety-one thousand, nine hundred thirteen".