1781321413 has 2 divisors, whose sum is σ = 1781321414. Its totient is φ = 1781321412.

The previous prime is 1781321407. The next prime is 1781321417. The reversal of 1781321413 is 3141231871.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1064260129 + 717061284 = 32623^2 + 26778^2 .

It is a cyclic number.

It is not a de Polignac number, because 1781321413 - 2¹³ = 1781313221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1781321417) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 890660706 + 890660707.

It is an arithmetic number, because the mean of its divisors is an integer number (890660707).

Almost surely, 2^1781321413 is an apocalyptic number.

It is an amenable number.

1781321413 is a deficient number, since it is larger than the sum of its proper divisors (1).

1781321413 is an equidigital number, since it uses as much as digits as its factorization.

1781321413 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4032, while the sum is 31.

The square root of 1781321413 is about 42205.7035600640. The cubic root of 1781321413 is about 1212.2180959111.

The spelling of 1781321413 in words is "one billion, seven hundred eighty-one million, three hundred twenty-one thousand, four hundred thirteen".