21211100120018 has 4 divisors (see below), whose sum is σ = 31816650180030. Its totient is φ = 10605550060008.

The previous prime is 21211100120017. The next prime is 21211100120059. The reversal of 21211100120018 is 81002100111212.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 19773434373289 + 1437665746729 = 4446733^2 + 1199027^2 .

It is a super-3 number, since 3×21211100120018³ (a number of 41 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not an unprimeable number, because it can be changed into a prime (21211100120011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5302775030003 + ... + 5302775030006.

Almost surely, 2^{21211100120018} is an apocalyptic number.

21211100120018 is a deficient number, since it is larger than the sum of its proper divisors (10605550060012).

21211100120018 is a wasteful number, since it uses less digits than its factorization.

21211100120018 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10605550060011.

The product of its (nonzero) digits is 64, while the sum is 20.

The spelling of 21211100120018 in words is "twenty-one trillion, two hundred eleven billion, one hundred million, one hundred twenty thousand, eighteen".