1918289431691 has 2 divisors, whose sum is σ = 1918289431692. Its totient is φ = 1918289431690.

The previous prime is 1918289431621. The next prime is 1918289431717. The reversal of 1918289431691 is 1961349828191.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1918289431691 - 2¹⁰ = 1918289430667 is a prime.

It is not a weakly prime, because it can be changed into another prime (1918289431621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 959144715845 + 959144715846.

It is an arithmetic number, because the mean of its divisors is an integer number (959144715846).

Almost surely, 2^{1918289431691} is an apocalyptic number.

1918289431691 is a deficient number, since it is larger than the sum of its proper divisors (1).

1918289431691 is an equidigital number, since it uses as much as digits as its factorization.

1918289431691 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6718464, while the sum is 62.

The spelling of 1918289431691 in words is "one trillion, nine hundred eighteen billion, two hundred eighty-nine million, four hundred thirty-one thousand, six hundred ninety-one".