1287959866 has 4 divisors (see below), whose sum is σ = 1931939802. Its totient is φ = 643979932.

The previous prime is 1287959843. The next prime is 1287959867. The reversal of 1287959866 is 6689597821.

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

It can be written as a sum of positive squares in only one way, i.e., 978375841 + 309584025 = 31279^2 + 17595^2 .

It is not an unprimeable number, because it can be changed into a prime (1287959867) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321989965 + ... + 321989968.

Almost surely, 2^1287959866 is an apocalyptic number.

1287959866 is a deficient number, since it is larger than the sum of its proper divisors (643979936).

1287959866 is an equidigital number, since it uses as much as digits as its factorization.

1287959866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 643979935.

The product of its digits is 13063680, while the sum is 61.

The square root of 1287959866 is about 35888.1577404023. The cubic root of 1287959866 is about 1088.0130640417.

The spelling of 1287959866 in words is "one billion, two hundred eighty-seven million, nine hundred fifty-nine thousand, eight hundred sixty-six".