1918373738509 has 2 divisors, whose sum is σ = 1918373738510. Its totient is φ = 1918373738508.

The previous prime is 1918373738507. The next prime is 1918373738531. The reversal of 1918373738509 is 9058373738191.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1678004162884 + 240369575625 = 1295378^2 + 490275^2 .

It is a cyclic number.

It is not a de Polignac number, because 1918373738509 - 2¹ = 1918373738507 is a prime.

Together with 1918373738507, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1918373738507) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 959186869254 + 959186869255.

It is an arithmetic number, because the mean of its divisors is an integer number (959186869255).

Almost surely, 2^{1918373738509} is an apocalyptic number.

It is an amenable number.

1918373738509 is a deficient number, since it is larger than the sum of its proper divisors (1).

1918373738509 is an equidigital number, since it uses as much as digits as its factorization.

1918373738509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34292160, while the sum is 64.

The spelling of 1918373738509 in words is "one trillion, nine hundred eighteen billion, three hundred seventy-three million, seven hundred thirty-eight thousand, five hundred nine".