21220021212011 has 4 divisors (see below), whose sum is σ = 22468257753912. Its totient is φ = 19971784670112.

The previous prime is 21220021211971. The next prime is 21220021212023. The reversal of 21220021212011 is 11021212002212.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21220021212011 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (17), and also a Moran number because the ratio is a prime number: 1248236541883 = 21220021212011 / (2 + 1 + 2 + 2 + 0 + 0 + 2 + 1 + 2 + 1 + 2 + 0 + 1 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21220021212031) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 624118270925 + ... + 624118270958.

It is an arithmetic number, because the mean of its divisors is an integer number (5617064438478).

Almost surely, 2^{21220021212011} is an apocalyptic number.

21220021212011 is a deficient number, since it is larger than the sum of its proper divisors (1248236541901).

21220021212011 is a wasteful number, since it uses less digits than its factorization.

21220021212011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1248236541900.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 21220021212011 its reverse (11021212002212), we get a palindrome (32241233214223).

The spelling of 21220021212011 in words is "twenty-one trillion, two hundred twenty billion, twenty-one million, two hundred twelve thousand, eleven".