18817898389 has 2 divisors, whose sum is σ = 18817898390. Its totient is φ = 18817898388.

The previous prime is 18817898377. The next prime is 18817898423. The reversal of 18817898389 is 98389871881.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18816980625 + 917764 = 137175^2 + 958^2 .

It is a cyclic number.

It is not a de Polignac number, because 18817898389 - 2⁷ = 18817898261 is a prime.

It is a super-2 number, since 2×18817898389² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18817898329) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9408949194 + 9408949195.

It is an arithmetic number, because the mean of its divisors is an integer number (9408949195).

Almost surely, 2^18817898389 is an apocalyptic number.

It is an amenable number.

18817898389 is a deficient number, since it is larger than the sum of its proper divisors (1).

18817898389 is an equidigital number, since it uses as much as digits as its factorization.

18817898389 is an evil number, because the sum of its binary digits is even.

The product of its digits is 55738368, while the sum is 70.

The spelling of 18817898389 in words is "eighteen billion, eight hundred seventeen million, eight hundred ninety-eight thousand, three hundred eighty-nine".