18399807449 has 2 divisors, whose sum is σ = 18399807450. Its totient is φ = 18399807448.

The previous prime is 18399807443. The next prime is 18399807463. The reversal of 18399807449 is 94470899381.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10347975625 + 8051831824 = 101725^2 + 89732^2 .

It is a cyclic number.

It is not a de Polignac number, because 18399807449 - 2³² = 14104840153 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 18399807391 and 18399807400.

It is not a weakly prime, because it can be changed into another prime (18399807443) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9199903724 + 9199903725.

It is an arithmetic number, because the mean of its divisors is an integer number (9199903725).

Almost surely, 2^18399807449 is an apocalyptic number.

It is an amenable number.

18399807449 is a deficient number, since it is larger than the sum of its proper divisors (1).

18399807449 is an equidigital number, since it uses as much as digits as its factorization.

18399807449 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15676416, while the sum is 62.

The spelling of 18399807449 in words is "eighteen billion, three hundred ninety-nine million, eight hundred seven thousand, four hundred forty-nine".