1287855839 has 4 divisors (see below), whose sum is σ = 1288024080. Its totient is φ = 1287687600.

The previous prime is 1287855827. The next prime is 1287855857. The reversal of 1287855839 is 9385587821.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1287855839 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1287855869) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 72062 + ... + 88139.

It is an arithmetic number, because the mean of its divisors is an integer number (322006020).

Almost surely, 2^1287855839 is an apocalyptic number.

1287855839 is a deficient number, since it is larger than the sum of its proper divisors (168241).

1287855839 is an equidigital number, since it uses as much as digits as its factorization.

1287855839 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 168240.

The product of its digits is 4838400, while the sum is 56.

The square root of 1287855839 is about 35886.7083890401. The cubic root of 1287855839 is about 1087.9837707422.

The spelling of 1287855839 in words is "one billion, two hundred eighty-seven million, eight hundred fifty-five thousand, eight hundred thirty-nine".