18868639997 has 2 divisors, whose sum is σ = 18868639998. Its totient is φ = 18868639996.

The previous prime is 18868639969. The next prime is 18868640009. The reversal of 18868639997 is 79993686881.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17195339161 + 1673300836 = 131131^2 + 40906^2 .

It is a cyclic number.

It is not a de Polignac number, because 18868639997 - 2¹⁰ = 18868638973 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18868632997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9434319998 + 9434319999.

It is an arithmetic number, because the mean of its divisors is an integer number (9434319999).

Almost surely, 2^18868639997 is an apocalyptic number.

It is an amenable number.

18868639997 is a deficient number, since it is larger than the sum of its proper divisors (1).

18868639997 is an equidigital number, since it uses as much as digits as its factorization.

18868639997 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 282175488, while the sum is 74.

The spelling of 18868639997 in words is "eighteen billion, eight hundred sixty-eight million, six hundred thirty-nine thousand, nine hundred ninety-seven".