18367021 has 4 divisors (see below), whose sum is σ = 19447452. Its totient is φ = 17286592.

The previous prime is 18367009. The next prime is 18367031. The reversal of 18367021 is 12076381.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12076381 = 19 ⋅635599.

It can be written as a sum of positive squares in 2 ways, for example, as 10329796 + 8037225 = 3214^2 + 2835^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18367021 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18367001) 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, 540190 + ... + 540223.

It is an arithmetic number, because the mean of its divisors is an integer number (4861863).

Almost surely, 2^18367021 is an apocalyptic number.

It is an amenable number.

18367021 is a deficient number, since it is larger than the sum of its proper divisors (1080431).

18367021 is a wasteful number, since it uses less digits than its factorization.

18367021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1080430.

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 18367021 is about 4285.6762593551. The cubic root of 18367021 is about 263.8434036486.

The spelling of 18367021 in words is "eighteen million, three hundred sixty-seven thousand, twenty-one".