1685287987 has 2 divisors, whose sum is σ = 1685287988. Its totient is φ = 1685287986.

The previous prime is 1685287969. The next prime is 1685288009. The reversal of 1685287987 is 7897825861.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1685287987 is a prime.

It is not a weakly prime, because it can be changed into another prime (1685287187) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 842643993 + 842643994.

It is an arithmetic number, because the mean of its divisors is an integer number (842643994).

Almost surely, 2^1685287987 is an apocalyptic number.

1685287987 is a deficient number, since it is larger than the sum of its proper divisors (1).

1685287987 is an equidigital number, since it uses as much as digits as its factorization.

1685287987 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13547520, while the sum is 61.

The square root of 1685287987 is about 41052.2592191952. The cubic root of 1685287987 is about 1190.0303612525.

The spelling of 1685287987 in words is "one billion, six hundred eighty-five million, two hundred eighty-seven thousand, nine hundred eighty-seven".