21505223341 has 6 divisors (see below), whose sum is σ = 25016280270. Its totient is φ = 18433048536.

The previous prime is 21505223291. The next prime is 21505223387. The reversal of 21505223341 is 14332250512.

It can be written as a sum of positive squares in only one way, i.e., 11313513225 + 10191710116 = 106365^2 + 100954^2 .

It is not a de Polignac number, because 21505223341 - 2⁹ = 21505222829 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 (21505223141) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 219441006 + ... + 219441103.

It is an arithmetic number, because the mean of its divisors is an integer number (4169380045).

Almost surely, 2^21505223341 is an apocalyptic number.

It is an amenable number.

21505223341 is a deficient number, since it is larger than the sum of its proper divisors (3511056929).

21505223341 is an equidigital number, since it uses as much as digits as its factorization.

21505223341 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 438882123 (or 438882116 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 28.

Adding to 21505223341 its reverse (14332250512), we get a palindrome (35837473853).

The spelling of 21505223341 in words is "twenty-one billion, five hundred five million, two hundred twenty-three thousand, three hundred forty-one".