21022405205221 has 32 divisors (see below), whose sum is σ = 24268973137920. Its totient is φ = 17837098831104.

The previous prime is 21022405205213. The next prime is 21022405205231. The reversal of 21022405205221 is 12250250422012.

It is not a de Polignac number, because 21022405205221 - 2³ = 21022405205213 is a prime.

It is a super-2 number, since 2×21022405205221² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21022405205221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21022405205231) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3010508496 + ... + 3010515478.

It is an arithmetic number, because the mean of its divisors is an integer number (758405410560).

Almost surely, 2^{21022405205221} is an apocalyptic number.

It is an amenable number.

21022405205221 is a deficient number, since it is larger than the sum of its proper divisors (3246567932699).

21022405205221 is a wasteful number, since it uses less digits than its factorization.

21022405205221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11385.

The product of its (nonzero) digits is 6400, while the sum is 28.

Adding to 21022405205221 its reverse (12250250422012), we get a palindrome (33272655627233).

The spelling of 21022405205221 in words is "twenty-one trillion, twenty-two billion, four hundred five million, two hundred five thousand, two hundred twenty-one".