18647677481 has 2 divisors, whose sum is σ = 18647677482. Its totient is φ = 18647677480.

The previous prime is 18647677421. The next prime is 18647677483. The reversal of 18647677481 is 18477674681.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15871968256 + 2775709225 = 125984^2 + 52685^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18647677481 is a prime.

It is a super-2 number, since 2×18647677481² (a number of 21 digits) contains 22 as substring.

Together with 18647677483, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18647677481.

It is not a weakly prime, because it can be changed into another prime (18647677483) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9323838740 + 9323838741.

It is an arithmetic number, because the mean of its divisors is an integer number (9323838741).

Almost surely, 2^18647677481 is an apocalyptic number.

It is an amenable number.

18647677481 is a deficient number, since it is larger than the sum of its proper divisors (1).

18647677481 is an equidigital number, since it uses as much as digits as its factorization.

18647677481 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12644352, while the sum is 59.

The spelling of 18647677481 in words is "eighteen billion, six hundred forty-seven million, six hundred seventy-seven thousand, four hundred eighty-one".