18680064649 has 2 divisors, whose sum is σ = 18680064650. Its totient is φ = 18680064648.

The previous prime is 18680064647. The next prime is 18680064659. The reversal of 18680064649 is 94646008681.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18521304649 + 158760000 = 136093^2 + 12600^2 .

It is a cyclic number.

It is not a de Polignac number, because 18680064649 - 2¹ = 18680064647 is a prime.

Together with 18680064647, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 18680064596 and 18680064605.

It is not a weakly prime, because it can be changed into another prime (18680064647) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9340032324 + 9340032325.

It is an arithmetic number, because the mean of its divisors is an integer number (9340032325).

Almost surely, 2^18680064649 is an apocalyptic number.

It is an amenable number.

18680064649 is a deficient number, since it is larger than the sum of its proper divisors (1).

18680064649 is an equidigital number, since it uses as much as digits as its factorization.

18680064649 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1990656, while the sum is 52.

The spelling of 18680064649 in words is "eighteen billion, six hundred eighty million, sixty-four thousand, six hundred forty-nine".