18138623 has 2 divisors, whose sum is σ = 18138624. Its totient is φ = 18138622.

The previous prime is 18138613. The next prime is 18138629. The reversal of 18138623 is 32683181.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18138623 - 2¹⁰ = 18137599 is a prime.

It is a super-2 number, since 2×18138623² = 658019288672258, which contains 22 as substring.

It is a Sophie Germain prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18138623.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18138629) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9069311 + 9069312.

It is an arithmetic number, because the mean of its divisors is an integer number (9069312).

Almost surely, 2^18138623 is an apocalyptic number.

18138623 is a deficient number, since it is larger than the sum of its proper divisors (1).

18138623 is an equidigital number, since it uses as much as digits as its factorization.

18138623 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6912, while the sum is 32.

The square root of 18138623 is about 4258.9462311703. The cubic root of 18138623 is about 262.7451882951.

The spelling of 18138623 in words is "eighteen million, one hundred thirty-eight thousand, six hundred twenty-three".