18944396281 has 2 divisors, whose sum is σ = 18944396282. Its totient is φ = 18944396280.

The previous prime is 18944396257. The next prime is 18944396287. The reversal of 18944396281 is 18269344981.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10965440656 + 7978955625 = 104716^2 + 89325^2 .

It is a cyclic number.

It is not a de Polignac number, because 18944396281 - 2⁵ = 18944396249 is a prime.

It is a super-2 number, since 2×18944396281² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18944396287) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9472198140 + 9472198141.

It is an arithmetic number, because the mean of its divisors is an integer number (9472198141).

Almost surely, 2^18944396281 is an apocalyptic number.

It is an amenable number.

18944396281 is a deficient number, since it is larger than the sum of its proper divisors (1).

18944396281 is an equidigital number, since it uses as much as digits as its factorization.

18944396281 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2985984, while the sum is 55.

The spelling of 18944396281 in words is "eighteen billion, nine hundred forty-four million, three hundred ninety-six thousand, two hundred eighty-one".