1685508663389 has 2 divisors, whose sum is σ = 1685508663390. Its totient is φ = 1685508663388.

The previous prime is 1685508663353. The next prime is 1685508663401. The reversal of 1685508663389 is 9833668055861.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1163198919289 + 522309744100 = 1078517^2 + 722710^2 .

It is a cyclic number.

It is not a de Polignac number, because 1685508663389 - 2³² = 1681213696093 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1685508663889) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 842754331694 + 842754331695.

It is an arithmetic number, because the mean of its divisors is an integer number (842754331695).

Almost surely, 2^{1685508663389} is an apocalyptic number.

It is an amenable number.

1685508663389 is a deficient number, since it is larger than the sum of its proper divisors (1).

1685508663389 is an equidigital number, since it uses as much as digits as its factorization.

1685508663389 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 223948800, while the sum is 68.

The spelling of 1685508663389 in words is "one trillion, six hundred eighty-five billion, five hundred eight million, six hundred sixty-three thousand, three hundred eighty-nine".