21110222001221 has 4 divisors (see below), whose sum is σ = 21111006007872. Its totient is φ = 21109437994572.

The previous prime is 21110222001203. The next prime is 21110222001251. The reversal of 21110222001221 is 12210022201112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21110222001221 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 21110222001221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21110222001251) 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 in 3 ways as a sum of consecutive naturals, for example, 391962935 + ... + 392016788.

It is an arithmetic number, because the mean of its divisors is an integer number (5277751501968).

Almost surely, 2^{21110222001221} is an apocalyptic number.

It is an amenable number.

21110222001221 is a deficient number, since it is larger than the sum of its proper divisors (784006651).

21110222001221 is an equidigital number, since it uses as much as digits as its factorization.

21110222001221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 784006650.

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

Adding to 21110222001221 its reverse (12210022201112), we get a palindrome (33320244202333).

The spelling of 21110222001221 in words is "twenty-one trillion, one hundred ten billion, two hundred twenty-two million, one thousand, two hundred twenty-one".