21220102202021 has 4 divisors (see below), whose sum is σ = 21225332697132. Its totient is φ = 21214871706912.

The previous prime is 21220102202003. The next prime is 21220102202069. The reversal of 21220102202021 is 12020220102212.

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 2 ways, for example, as 14597786697025 + 6622315504996 = 3820705^2 + 2573386^2 .

It is a cyclic number.

It is not a de Polignac number, because 21220102202021 - 2⁶ = 21220102201957 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21220102202071) 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, 2615241470 + ... + 2615249583.

It is an arithmetic number, because the mean of its divisors is an integer number (5306333174283).

Almost surely, 2^{21220102202021} is an apocalyptic number.

It is an amenable number.

21220102202021 is a deficient number, since it is larger than the sum of its proper divisors (5230495111).

21220102202021 is an equidigital number, since it uses as much as digits as its factorization.

21220102202021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5230495110.

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

Adding to 21220102202021 its reverse (12020220102212), we get a palindrome (33240322304233).

The spelling of 21220102202021 in words is "twenty-one trillion, two hundred twenty billion, one hundred two million, two hundred two thousand, twenty-one".