18021023 has 4 divisors (see below), whose sum is σ = 18089808. Its totient is φ = 17952240.

The previous prime is 18020993. The next prime is 18021053. The reversal of 18021023 is 32012081.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (18020993) and next prime (18021053).

It is a cyclic number.

It is not a de Polignac number, because 18021023 - 2⁸ = 18020767 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18020992 and 18021010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18021053) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33998 + ... + 34523.

It is an arithmetic number, because the mean of its divisors is an integer number (4522452).

Almost surely, 2^18021023 is an apocalyptic number.

18021023 is a deficient number, since it is larger than the sum of its proper divisors (68785).

18021023 is an equidigital number, since it uses as much as digits as its factorization.

18021023 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68784.

The product of its (nonzero) digits is 96, while the sum is 17.

The square root of 18021023 is about 4245.1175484314. The cubic root of 18021023 is about 262.1761290702.

Subtracting from 18021023 its sum of digits (17), we obtain a triangular number (18021006 = T₆₀₀₃).

The spelling of 18021023 in words is "eighteen million, twenty-one thousand, twenty-three".