1287861313 has 4 divisors (see below), whose sum is σ = 1290920788. Its totient is φ = 1284801840.

The previous prime is 1287861301. The next prime is 1287861317. The reversal of 1287861313 is 3131687821.

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

It can be written as a sum of positive squares in 2 ways, for example, as 125596849 + 1162264464 = 11207^2 + 34092^2 .

It is a cyclic number.

It is not a de Polignac number, because 1287861313 - 2²⁵ = 1254306881 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1287861317) 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, 1529106 + ... + 1529947.

It is an arithmetic number, because the mean of its divisors is an integer number (322730197).

Almost surely, 2^1287861313 is an apocalyptic number.

It is an amenable number.

1287861313 is a deficient number, since it is larger than the sum of its proper divisors (3059475).

1287861313 is an equidigital number, since it uses as much as digits as its factorization.

1287861313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3059474.

The product of its digits is 48384, while the sum is 40.

The square root of 1287861313 is about 35886.7846567507. The cubic root of 1287861313 is about 1087.9853122229.

The spelling of 1287861313 in words is "one billion, two hundred eighty-seven million, eight hundred sixty-one thousand, three hundred thirteen".