18012021 has 4 divisors (see below), whose sum is σ = 24016032. Its totient is φ = 12008012.

The previous prime is 18012017. The next prime is 18012041. The reversal of 18012021 is 12021081.

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.

It is a cyclic number.

It is not a de Polignac number, because 18012021 - 2² = 18012017 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18012041) 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, 3002001 + ... + 3002006.

It is an arithmetic number, because the mean of its divisors is an integer number (6004008).

Almost surely, 2^18012021 is an apocalyptic number.

It is an amenable number.

18012021 is a deficient number, since it is larger than the sum of its proper divisors (6004011).

18012021 is an equidigital number, since it uses as much as digits as its factorization.

18012021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6004010.

The product of its (nonzero) digits is 32, while the sum is 15.

The square root of 18012021 is about 4244.0571391064. The cubic root of 18012021 is about 262.1324670538.

The spelling of 18012021 in words is "eighteen million, twelve thousand, twenty-one".