18491018449 has 2 divisors, whose sum is σ = 18491018450. Its totient is φ = 18491018448.

The previous prime is 18491018431. The next prime is 18491018537. The reversal of 18491018449 is 94481019481.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15877764049 + 2613254400 = 126007^2 + 51120^2 .

It is a cyclic number.

It is not a de Polignac number, because 18491018449 - 2⁵ = 18491018417 is a prime.

It is not a weakly prime, because it can be changed into another prime (18491018149) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9245509224 + 9245509225.

It is an arithmetic number, because the mean of its divisors is an integer number (9245509225).

Almost surely, 2^18491018449 is an apocalyptic number.

It is an amenable number.

18491018449 is a deficient number, since it is larger than the sum of its proper divisors (1).

18491018449 is an equidigital number, since it uses as much as digits as its factorization.

18491018449 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 331776, while the sum is 49.

The spelling of 18491018449 in words is "eighteen billion, four hundred ninety-one million, eighteen thousand, four hundred forty-nine".