18440619649 has 2 divisors, whose sum is σ = 18440619650. Its totient is φ = 18440619648.

The previous prime is 18440619641. The next prime is 18440619697. The reversal of 18440619649 is 94691604481.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18260657424 + 179962225 = 135132^2 + 13415^2 .

It is an emirp because it is prime and its reverse (94691604481) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18440619649 - 2³ = 18440619641 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 18440619596 and 18440619605.

It is not a weakly prime, because it can be changed into another prime (18440619641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9220309824 + 9220309825.

It is an arithmetic number, because the mean of its divisors is an integer number (9220309825).

Almost surely, 2^18440619649 is an apocalyptic number.

It is an amenable number.

18440619649 is a deficient number, since it is larger than the sum of its proper divisors (1).

18440619649 is an equidigital number, since it uses as much as digits as its factorization.

18440619649 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1492992, while the sum is 52.

The spelling of 18440619649 in words is "eighteen billion, four hundred forty million, six hundred nineteen thousand, six hundred forty-nine".