21011012022221 has 8 divisors (see below), whose sum is σ = 22628913443640. Its totient is φ = 19393349133312.

The previous prime is 21011012022151. The next prime is 21011012022239. The reversal of 21011012022221 is 12222021011012.

It can be written as a sum of positive squares in 4 ways, for example, as 39063546025 + 20971948476196 = 197645^2 + 4579514^2 .

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-21011012022221 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21011012022221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21011012022241) 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, 59450156 + ... + 59802533.

It is an arithmetic number, because the mean of its divisors is an integer number (2828614180455).

Almost surely, 2^{21011012022221} is an apocalyptic number.

It is an amenable number.

21011012022221 is a deficient number, since it is larger than the sum of its proper divisors (1617901421419).

21011012022221 is a wasteful number, since it uses less digits than its factorization.

21011012022221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 119266255.

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

Adding to 21011012022221 its reverse (12222021011012), we get a palindrome (33233033033233).

The spelling of 21011012022221 in words is "twenty-one trillion, eleven billion, twelve million, twenty-two thousand, two hundred twenty-one".