18123021613 has 2 divisors, whose sum is σ = 18123021614. Its totient is φ = 18123021612.

The previous prime is 18123021611. The next prime is 18123021619. The reversal of 18123021613 is 31612032181.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10798742889 + 7324278724 = 103917^2 + 85582^2 .

It is an emirp because it is prime and its reverse (31612032181) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18123021613 - 2¹ = 18123021611 is a prime.

Together with 18123021611, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18123021611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9061510806 + 9061510807.

It is an arithmetic number, because the mean of its divisors is an integer number (9061510807).

Almost surely, 2^18123021613 is an apocalyptic number.

It is an amenable number.

18123021613 is a deficient number, since it is larger than the sum of its proper divisors (1).

18123021613 is an equidigital number, since it uses as much as digits as its factorization.

18123021613 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1728, while the sum is 28.

Adding to 18123021613 its reverse (31612032181), we get a palindrome (49735053794).

The spelling of 18123021613 in words is "eighteen billion, one hundred twenty-three million, twenty-one thousand, six hundred thirteen".