1315781 has 2 divisors, whose sum is σ = 1315782. Its totient is φ = 1315780.

The previous prime is 1315771. The next prime is 1315801. The reversal of 1315781 is 1875131.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1288225 + 27556 = 1135^2 + 166^2 .

It is an emirp because it is prime and its reverse (1875131) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1315781 is a prime.

It is a super-2 number, since 2×1315781² = 3462559279922, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1315781.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1315711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 657890 + 657891.

It is an arithmetic number, because the mean of its divisors is an integer number (657891).

2^1315781 is an apocalyptic number.

It is an amenable number.

1315781 is a deficient number, since it is larger than the sum of its proper divisors (1).

1315781 is an equidigital number, since it uses as much as digits as its factorization.

1315781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 840, while the sum is 26.

The square root of 1315781 is about 1147.0749757535. The cubic root of 1315781 is about 109.5791356113.

The spelling of 1315781 in words is "one million, three hundred fifteen thousand, seven hundred eighty-one".