18022021 has 8 divisors (see below), whose sum is σ = 18901080. Its totient is φ = 17160192.

The previous prime is 18022019. The next prime is 18022027. The reversal of 18022021 is 12022081.

It can be written as a sum of positive squares in 4 ways, for example, as 8473921 + 9548100 = 2911^2 + 3090^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18022021 - 2¹ = 18022019 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18021986 and 18022004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18022027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2140 + ... + 6373.

It is an arithmetic number, because the mean of its divisors is an integer number (2362635).

Almost surely, 2^18022021 is an apocalyptic number.

It is an amenable number.

18022021 is a deficient number, since it is larger than the sum of its proper divisors (879059).

18022021 is an equidigital number, since it uses as much as digits as its factorization.

18022021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8615.

The product of its (nonzero) digits is 64, while the sum is 16.

The square root of 18022021 is about 4245.2350936079. The cubic root of 18022021 is about 262.1809687315.

It can be divided in two parts, 180 and 22021, that added together give a square (22201 = 149²).

The spelling of 18022021 in words is "eighteen million, twenty-two thousand, twenty-one".