21000122022221 has 8 divisors (see below), whose sum is σ = 21005950253760. Its totient is φ = 20994294226752.

The previous prime is 21000122022203. The next prime is 21000122022227. The reversal of 21000122022221 is 12222022100012.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21000122022221 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21000122022221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000122022227) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 111871640 + ... + 112059198.

It is an arithmetic number, because the mean of its divisors is an integer number (2625743781720).

Almost surely, 2^{21000122022221} is an apocalyptic number.

It is an amenable number.

21000122022221 is a deficient number, since it is larger than the sum of its proper divisors (5828231539).

21000122022221 is a wasteful number, since it uses less digits than its factorization.

21000122022221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 218035.

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 21000122022221 its reverse (12222022100012), we get a palindrome (33222144122233).

The spelling of 21000122022221 in words is "twenty-one trillion, one hundred twenty-two million, twenty-two thousand, two hundred twenty-one".