18943624081849 has 2 divisors, whose sum is σ = 18943624081850. Its totient is φ = 18943624081848.

The previous prime is 18943624081829. The next prime is 18943624081883. The reversal of 18943624081849 is 94818042634981.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13846347060624 + 5097277021225 = 3721068^2 + 2257715^2 .

It is a cyclic number.

It is not a de Polignac number, because 18943624081849 - 2¹⁷ = 18943623950777 is a prime.

It is not a weakly prime, because it can be changed into another prime (18943624081829) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9471812040924 + 9471812040925.

It is an arithmetic number, because the mean of its divisors is an integer number (9471812040925).

Almost surely, 2^{18943624081849} is an apocalyptic number.

It is an amenable number.

18943624081849 is a deficient number, since it is larger than the sum of its proper divisors (1).

18943624081849 is an equidigital number, since it uses as much as digits as its factorization.

18943624081849 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 95551488, while the sum is 67.

The spelling of 18943624081849 in words is "eighteen trillion, nine hundred forty-three billion, six hundred twenty-four million, eighty-one thousand, eight hundred forty-nine".