20001211218 has 12 divisors (see below), whose sum is σ = 43335957678. Its totient is φ = 6667070400.

The previous prime is 20001211211. The next prime is 20001211273. The reversal of 20001211218 is 81211210002.

It can be written as a sum of positive squares in only one way, i.e., 16610827689 + 3390383529 = 128883^2 + 58227^2 .

It is a Harshad number since it is a multiple of its sum of digits (18), and also a Moran number because the ratio is a prime number: 1111178401 = 20001211218 / (2 + 0 + 0 + 0 + 1 + 2 + 1 + 1 + 2 + 1 + 8).

It is a self number, because there is not a number n which added to its sum of digits gives 20001211218.

It is not an unprimeable number, because it can be changed into a prime (20001211211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 555589183 + ... + 555589218.

Almost surely, 2^20001211218 is an apocalyptic number.

20001211218 is an abundant number, since it is smaller than the sum of its proper divisors (23334746460).

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

20001211218 is a wasteful number, since it uses less digits than its factorization.

20001211218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1111178409 (or 1111178406 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

The spelling of 20001211218 in words is "twenty billion, one million, two hundred eleven thousand, two hundred eighteen".