1805440807889 has 2 divisors, whose sum is σ = 1805440807890. Its totient is φ = 1805440807888.

The previous prime is 1805440807817. The next prime is 1805440807931. The reversal of 1805440807889 is 9887080445081.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1504707022225 + 300733785664 = 1226665^2 + 548392^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1805440807889 is a prime.

It is not a weakly prime, because it can be changed into another prime (1805440807189) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 902720403944 + 902720403945.

It is an arithmetic number, because the mean of its divisors is an integer number (902720403945).

Almost surely, 2^{1805440807889} is an apocalyptic number.

It is an amenable number.

1805440807889 is a deficient number, since it is larger than the sum of its proper divisors (1).

1805440807889 is an equidigital number, since it uses as much as digits as its factorization.

1805440807889 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20643840, while the sum is 62.

The spelling of 1805440807889 in words is "one trillion, eight hundred five billion, four hundred forty million, eight hundred seven thousand, eight hundred eighty-nine".