1287681886 has 4 divisors (see below), whose sum is σ = 1931522832. Its totient is φ = 643840942.

The previous prime is 1287681883. The next prime is 1287681919. The reversal of 1287681886 is 6881867821.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1287681883) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321920470 + ... + 321920473.

It is an arithmetic number, because the mean of its divisors is an integer number (482880708).

Almost surely, 2^1287681886 is an apocalyptic number.

1287681886 is a deficient number, since it is larger than the sum of its proper divisors (643840946).

1287681886 is an equidigital number, since it uses as much as digits as its factorization.

1287681886 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 643840945.

The product of its digits is 2064384, while the sum is 55.

The square root of 1287681886 is about 35884.2846661321. The cubic root of 1287681886 is about 1087.9347832295.

The spelling of 1287681886 in words is "one billion, two hundred eighty-seven million, six hundred eighty-one thousand, eight hundred eighty-six".