18805637491 has 2 divisors, whose sum is σ = 18805637492. Its totient is φ = 18805637490.

The previous prime is 18805637489. The next prime is 18805637503. The reversal of 18805637491 is 19473650881.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18805637491 - 2¹ = 18805637489 is a prime.

Together with 18805637489, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (18805637441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9402818745 + 9402818746.

It is an arithmetic number, because the mean of its divisors is an integer number (9402818746).

Almost surely, 2^18805637491 is an apocalyptic number.

18805637491 is a deficient number, since it is larger than the sum of its proper divisors (1).

18805637491 is an equidigital number, since it uses as much as digits as its factorization.

18805637491 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1451520, while the sum is 52.

The spelling of 18805637491 in words is "eighteen billion, eight hundred five million, six hundred thirty-seven thousand, four hundred ninety-one".