18252021 has 4 divisors (see below), whose sum is σ = 24336032. Its totient is φ = 12168012.

The previous prime is 18252001. The next prime is 18252023. The reversal of 18252021 is 12025281.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12025281 = 3 ⋅4008427.

It is not a de Polignac number, because 18252021 - 2⁶ = 18251957 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 (18252023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3042001 + ... + 3042006.

It is an arithmetic number, because the mean of its divisors is an integer number (6084008).

Almost surely, 2^18252021 is an apocalyptic number.

It is an amenable number.

18252021 is a deficient number, since it is larger than the sum of its proper divisors (6084011).

18252021 is an equidigital number, since it uses as much as digits as its factorization.

18252021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6084010.

The product of its (nonzero) digits is 320, while the sum is 21.

The square root of 18252021 is about 4272.2384062690. The cubic root of 18252021 is about 263.2915896373.

The spelling of 18252021 in words is "eighteen million, two hundred fifty-two thousand, twenty-one".