18319820447 has 2 divisors, whose sum is σ = 18319820448. Its totient is φ = 18319820446.

The previous prime is 18319820399. The next prime is 18319820509. The reversal of 18319820447 is 74402891381.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18319820447 - 2¹⁰ = 18319819423 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18319820647) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9159910223 + 9159910224.

It is an arithmetic number, because the mean of its divisors is an integer number (9159910224).

Almost surely, 2^18319820447 is an apocalyptic number.

18319820447 is a deficient number, since it is larger than the sum of its proper divisors (1).

18319820447 is an equidigital number, since it uses as much as digits as its factorization.

18319820447 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 387072, while the sum is 47.

The spelling of 18319820447 in words is "eighteen billion, three hundred nineteen million, eight hundred twenty thousand, four hundred forty-seven".