1685131897 has 2 divisors, whose sum is σ = 1685131898. Its totient is φ = 1685131896.

The previous prime is 1685131849. The next prime is 1685131949. The reversal of 1685131897 is 7981315861.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 978688656 + 706443241 = 31284^2 + 26579^2 .

It is a cyclic number.

It is not a de Polignac number, because 1685131897 - 2⁷ = 1685131769 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1685131897.

It is not a weakly prime, because it can be changed into another prime (1685131297) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 842565948 + 842565949.

It is an arithmetic number, because the mean of its divisors is an integer number (842565949).

Almost surely, 2^1685131897 is an apocalyptic number.

It is an amenable number.

1685131897 is a deficient number, since it is larger than the sum of its proper divisors (1).

1685131897 is an equidigital number, since it uses as much as digits as its factorization.

1685131897 is an evil number, because the sum of its binary digits is even.

The product of its digits is 362880, while the sum is 49.

The square root of 1685131897 is about 41050.3580617758. The cubic root of 1685131897 is about 1189.9936202374.

The spelling of 1685131897 in words is "one billion, six hundred eighty-five million, one hundred thirty-one thousand, eight hundred ninety-seven".