18850404581 has 2 divisors, whose sum is σ = 18850404582. Its totient is φ = 18850404580.

The previous prime is 18850404527. The next prime is 18850404619. The reversal of 18850404581 is 18540405881.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18700562500 + 149842081 = 136750^2 + 12241^2 .

It is a cyclic number.

It is not a de Polignac number, because 18850404581 - 2¹⁴ = 18850388197 is a prime.

It is a super-2 number, since 2×18850404581² (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 (18850406581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9425202290 + 9425202291.

It is an arithmetic number, because the mean of its divisors is an integer number (9425202291).

Almost surely, 2^18850404581 is an apocalyptic number.

It is an amenable number.

18850404581 is a deficient number, since it is larger than the sum of its proper divisors (1).

18850404581 is an equidigital number, since it uses as much as digits as its factorization.

18850404581 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 204800, while the sum is 44.

The spelling of 18850404581 in words is "eighteen billion, eight hundred fifty million, four hundred four thousand, five hundred eighty-one".