18840647381 has 2 divisors, whose sum is σ = 18840647382. Its totient is φ = 18840647380.

The previous prime is 18840647351. The next prime is 18840647411. The reversal of 18840647381 is 18374604881.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (18840647351) and next prime (18840647411).

It can be written as a sum of positive squares in only one way, i.e., 10197970225 + 8642677156 = 100985^2 + 92966^2 .

It is a cyclic number.

It is not a de Polignac number, because 18840647381 - 2¹⁴ = 18840630997 is a prime.

It is a super-2 number, since 2×18840647381² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18840647321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9420323690 + 9420323691.

It is an arithmetic number, because the mean of its divisors is an integer number (9420323691).

Almost surely, 2^18840647381 is an apocalyptic number.

It is an amenable number.

18840647381 is a deficient number, since it is larger than the sum of its proper divisors (1).

18840647381 is an equidigital number, since it uses as much as digits as its factorization.

18840647381 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1032192, while the sum is 50.

The spelling of 18840647381 in words is "eighteen billion, eight hundred forty million, six hundred forty-seven thousand, three hundred eighty-one".