1823115781 has 2 divisors, whose sum is σ = 1823115782. Its totient is φ = 1823115780.

The previous prime is 1823115779. The next prime is 1823115817. The reversal of 1823115781 is 1875113281.

It is a happy number.

Together with next prime (1823115817) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1805400100 + 17715681 = 42490^2 + 4209^2 .

It is a cyclic number.

It is not a de Polignac number, because 1823115781 - 2¹ = 1823115779 is a prime.

It is a super-2 number, since 2×1823115781² = 6647502301862479922, which contains 22 as substring.

Together with 1823115779, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 1823115781.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1823115731) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 911557890 + 911557891.

It is an arithmetic number, because the mean of its divisors is an integer number (911557891).

Almost surely, 2^1823115781 is an apocalyptic number.

It is an amenable number.

1823115781 is a deficient number, since it is larger than the sum of its proper divisors (1).

1823115781 is an equidigital number, since it uses as much as digits as its factorization.

1823115781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13440, while the sum is 37.

The square root of 1823115781 is about 42697.9599161365. The cubic root of 1823115781 is about 1221.6254829062.

The spelling of 1823115781 in words is "one billion, eight hundred twenty-three million, one hundred fifteen thousand, seven hundred eighty-one".