1287671813 has 4 divisors (see below), whose sum is σ = 1343657568. Its totient is φ = 1231686060.

The previous prime is 1287671779. The next prime is 1287671821. The reversal of 1287671813 is 3181767821.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 3181767821 = 17 ⋅187162813.

It is a cyclic number.

It is not a de Polignac number, because 1287671813 - 2⁸ = 1287671557 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 (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, 27992843 + ... + 27992888.

It is an arithmetic number, because the mean of its divisors is an integer number (335914392).

Almost surely, 2^1287671813 is an apocalyptic number.

It is an amenable number.

1287671813 is a deficient number, since it is larger than the sum of its proper divisors (55985755).

1287671813 is an equidigital number, since it uses as much as digits as its factorization.

1287671813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55985754.

The product of its digits is 112896, while the sum is 44.

The square root of 1287671813 is about 35884.1443119381. The cubic root of 1287671813 is about 1087.9319464016.

The spelling of 1287671813 in words is "one billion, two hundred eighty-seven million, six hundred seventy-one thousand, eight hundred thirteen".