18021812 has 24 divisors (see below), whose sum is σ = 32583936. Its totient is φ = 8715168.

The previous prime is 18021799. The next prime is 18021827. The reversal of 18021812 is 21812081.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38693 + ... + 39155.

It is an arithmetic number, because the mean of its divisors is an integer number (1357664).

Almost surely, 2^18021812 is an apocalyptic number.

It is an amenable number.

18021812 is a deficient number, since it is larger than the sum of its proper divisors (14562124).

18021812 is a wasteful number, since it uses less digits than its factorization.

18021812 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 767 (or 765 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 23.

The square root of 18021812 is about 4245.2104777031. The cubic root of 18021812 is about 262.1799552301.

Adding to 18021812 its reverse (21812081), we get a palindrome (39833893).

The spelling of 18021812 in words is "eighteen million, twenty-one thousand, eight hundred twelve".