1286138321 has 4 divisors (see below), whose sum is σ = 1385072052. Its totient is φ = 1187204592.

The previous prime is 1286138317. The next prime is 1286138339. The reversal of 1286138321 is 1238316821.

It is a happy number.

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 100300225 + 1185838096 = 10015^2 + 34436^2 .

It is a cyclic number.

It is not a de Polignac number, because 1286138321 - 2² = 1286138317 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1286138341) 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, 49466846 + ... + 49466871.

It is an arithmetic number, because the mean of its divisors is an integer number (346268013).

Almost surely, 2^1286138321 is an apocalyptic number.

It is an amenable number.

1286138321 is a deficient number, since it is larger than the sum of its proper divisors (98933731).

1286138321 is an equidigital number, since it uses as much as digits as its factorization.

1286138321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 98933730.

The product of its digits is 13824, while the sum is 35.

The square root of 1286138321 is about 35862.7706821433. The cubic root of 1286138321 is about 1087.4999011054.

The spelling of 1286138321 in words is "one billion, two hundred eighty-six million, one hundred thirty-eight thousand, three hundred twenty-one".