20311218 has 24 divisors (see below), whose sum is σ = 44465148. Its totient is φ = 6700032.

The previous prime is 20311211. The next prime is 20311273. The reversal of 20311218 is 81211302.

It can be written as a sum of positive squares in 2 ways, for example, as 20223009 + 88209 = 4497^2 + 297^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a self number, because there is not a number n which added to its sum of digits gives 20311218.

It is not an unprimeable number, because it can be changed into a prime (20311211) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4071 + ... + 7562.

Almost surely, 2^20311218 is an apocalyptic number.

20311218 is an abundant number, since it is smaller than the sum of its proper divisors (24153930).

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

20311218 is a wasteful number, since it uses less digits than its factorization.

20311218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11738 (or 11735 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

The square root of 20311218 is about 4506.7968669555. The cubic root of 20311218 is about 272.8424804776.

It can be divided in two parts, 2031 and 1218, that added together give a square (3249 = 57²).

The spelling of 20311218 in words is "twenty million, three hundred eleven thousand, two hundred eighteen".