18737140781 has 2 divisors, whose sum is σ = 18737140782. Its totient is φ = 18737140780.

The previous prime is 18737140771. The next prime is 18737140859. The reversal of 18737140781 is 18704173781.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13171234756 + 5565906025 = 114766^2 + 74605^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18737140781 is a prime.

It is a super-2 number, since 2×18737140781² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18737140771) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9368570390 + 9368570391.

It is an arithmetic number, because the mean of its divisors is an integer number (9368570391).

Almost surely, 2^18737140781 is an apocalyptic number.

It is an amenable number.

18737140781 is a deficient number, since it is larger than the sum of its proper divisors (1).

18737140781 is an equidigital number, since it uses as much as digits as its factorization.

18737140781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 263424, while the sum is 47.

The spelling of 18737140781 in words is "eighteen billion, seven hundred thirty-seven million, one hundred forty thousand, seven hundred eighty-one".