1287671845 has 4 divisors (see below), whose sum is σ = 1545206220. Its totient is φ = 1030137472.

The previous prime is 1287671843. The next prime is 1287671849. The reversal of 1287671845 is 5481767821.

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 935809281 + 351862564 = 30591^2 + 18758^2 .

It is a cyclic number.

It is not a de Polignac number, because 1287671845 - 2¹ = 1287671843 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1287671843) 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, 128767180 + ... + 128767189.

It is an arithmetic number, because the mean of its divisors is an integer number (386301555).

Almost surely, 2^1287671845 is an apocalyptic number.

It is an amenable number.

1287671845 is a deficient number, since it is larger than the sum of its proper divisors (257534375).

1287671845 is an equidigital number, since it uses as much as digits as its factorization.

1287671845 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 257534374.

The product of its digits is 752640, while the sum is 49.

The square root of 1287671845 is about 35884.1447578175. The cubic root of 1287671845 is about 1087.9319554137.

The spelling of 1287671845 in words is "one billion, two hundred eighty-seven million, six hundred seventy-one thousand, eight hundred forty-five".