1306831721 has 8 divisors (see below), whose sum is σ = 1409804424. Its totient is φ = 1204208640.

The previous prime is 1306831703. The next prime is 1306831783. The reversal of 1306831721 is 1271386031.

It can be written as a sum of positive squares in 4 ways, for example, as 63282025 + 1243549696 = 7955^2 + 35264^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1306831721 - 2³⁰ = 233089897 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1306831621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 79610 + ... + 94611.

It is an arithmetic number, because the mean of its divisors is an integer number (176225553).

Almost surely, 2^1306831721 is an apocalyptic number.

It is an amenable number.

1306831721 is a deficient number, since it is larger than the sum of its proper divisors (102972703).

1306831721 is a wasteful number, since it uses less digits than its factorization.

1306831721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 174811.

The product of its (nonzero) digits is 6048, while the sum is 32.

The square root of 1306831721 is about 36150.1275378110. The cubic root of 1306831721 is about 1093.3013622067.

The spelling of 1306831721 in words is "one billion, three hundred six million, eight hundred thirty-one thousand, seven hundred twenty-one".