21021010202221 has 4 divisors (see below), whose sum is σ = 21021241366944. Its totient is φ = 21020779037500.

The previous prime is 21021010202161. The next prime is 21021010202261. The reversal of 21021010202221 is 12220201012012.

It is a happy number.

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 not a de Polignac number, because 21021010202221 - 2¹⁹ = 21021009677933 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21021010202195 and 21021010202204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021010202261) 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, 115445905 + ... + 115627846.

It is an arithmetic number, because the mean of its divisors is an integer number (5255310341736).

Almost surely, 2^{21021010202221} is an apocalyptic number.

It is an amenable number.

21021010202221 is a deficient number, since it is larger than the sum of its proper divisors (231164723).

21021010202221 is an equidigital number, since it uses as much as digits as its factorization.

21021010202221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 231164722.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21021010202221 its reverse (12220201012012), we get a palindrome (33241211214233).

The spelling of 21021010202221 in words is "twenty-one trillion, twenty-one billion, ten million, two hundred two thousand, two hundred twenty-one".