1687397897 has 2 divisors, whose sum is σ = 1687397898. Its totient is φ = 1687397896.

The previous prime is 1687397861. The next prime is 1687397939. The reversal of 1687397897 is 7987937861.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1348064656 + 339333241 = 36716^2 + 18421^2 .

It is a cyclic number.

It is not a de Polignac number, because 1687397897 - 2⁸ = 1687397641 is a prime.

It is not a weakly prime, because it can be changed into another prime (1687397827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 843698948 + 843698949.

It is an arithmetic number, because the mean of its divisors is an integer number (843698949).

Almost surely, 2^1687397897 is an apocalyptic number.

It is an amenable number.

1687397897 is a deficient number, since it is larger than the sum of its proper divisors (1).

1687397897 is an equidigital number, since it uses as much as digits as its factorization.

1687397897 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 32006016, while the sum is 65.

The square root of 1687397897 is about 41077.9490359487. The cubic root of 1687397897 is about 1190.5267768756.

The spelling of 1687397897 in words is "one billion, six hundred eighty-seven million, three hundred ninety-seven thousand, eight hundred ninety-seven".