18363801649 has 2 divisors, whose sum is σ = 18363801650. Its totient is φ = 18363801648.

The previous prime is 18363801637. The next prime is 18363801721. The reversal of 18363801649 is 94610836381.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16687472400 + 1676329249 = 129180^2 + 40943^2 .

It is an emirp because it is prime and its reverse (94610836381) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18363801649 - 2¹⁵ = 18363768881 is a prime.

It is a super-2 number, since 2×18363801649² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18363801629) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9181900824 + 9181900825.

It is an arithmetic number, because the mean of its divisors is an integer number (9181900825).

Almost surely, 2^18363801649 is an apocalyptic number.

It is an amenable number.

18363801649 is a deficient number, since it is larger than the sum of its proper divisors (1).

18363801649 is an equidigital number, since it uses as much as digits as its factorization.

18363801649 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 746496, while the sum is 49.

The spelling of 18363801649 in words is "eighteen billion, three hundred sixty-three million, eight hundred one thousand, six hundred forty-nine".