1281315691 has 4 divisors (see below), whose sum is σ = 1293290712. Its totient is φ = 1269340672.

The previous prime is 1281315689. The next prime is 1281315703. The reversal of 1281315691 is 1965131821.

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

It is a cyclic number.

It is not a de Polignac number, because 1281315691 - 2¹ = 1281315689 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1281315691.

It is not an unprimeable number, because it can be changed into a prime (1281315631) 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, 5987350 + ... + 5987563.

It is an arithmetic number, because the mean of its divisors is an integer number (323322678).

Almost surely, 2^1281315691 is an apocalyptic number.

1281315691 is a deficient number, since it is larger than the sum of its proper divisors (11975021).

1281315691 is a wasteful number, since it uses less digits than its factorization.

1281315691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11975020.

The product of its digits is 12960, while the sum is 37.

The square root of 1281315691 is about 35795.4702581206. The cubic root of 1281315691 is about 1086.1389332929.

The spelling of 1281315691 in words is "one billion, two hundred eighty-one million, three hundred fifteen thousand, six hundred ninety-one".