18249009491 has 2 divisors, whose sum is σ = 18249009492. Its totient is φ = 18249009490.

The previous prime is 18249009479. The next prime is 18249009523. The reversal of 18249009491 is 19490094281.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18249009491 - 2¹⁸ = 18248747347 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (18249009421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9124504745 + 9124504746.

It is an arithmetic number, because the mean of its divisors is an integer number (9124504746).

Almost surely, 2^18249009491 is an apocalyptic number.

18249009491 is a deficient number, since it is larger than the sum of its proper divisors (1).

18249009491 is an equidigital number, since it uses as much as digits as its factorization.

18249009491 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 186624, while the sum is 47.

The spelling of 18249009491 in words is "eighteen billion, two hundred forty-nine million, nine thousand, four hundred ninety-one".