21318018 has 16 divisors (see below), whose sum is σ = 44011776. Its totient is φ = 6876720.

The previous prime is 21318007. The next prime is 21318047. The reversal of 21318018 is 81081312.

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, 57121 + ... + 57492.

It is an arithmetic number, because the mean of its divisors is an integer number (2750736).

Almost surely, 2^21318018 is an apocalyptic number.

21318018 is an abundant number, since it is smaller than the sum of its proper divisors (22693758).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21318018 is a wasteful number, since it uses less digits than its factorization.

21318018 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 114649.

The product of its (nonzero) digits is 384, while the sum is 24.

The square root of 21318018 is about 4617.1439223832. The cubic root of 21318018 is about 277.2781247327.

The spelling of 21318018 in words is "twenty-one million, three hundred eighteen thousand, eighteen".