21350505321 has 6 divisors (see below), whose sum is σ = 30839618810. Its totient is φ = 14233670208.

The previous prime is 21350505311. The next prime is 21350505329. The reversal of 21350505321 is 12350505312.

It is a happy number.

21350505321 is a `hidden beast` number, since 2 + 135 + 0 + 505 + 3 + 21 = 666.

It can be written as a sum of positive squares in only one way, i.e., 21152793600 + 197711721 = 145440^2 + 14061^2 .

It is not a de Polignac number, because 21350505321 - 2¹⁴ = 21350488937 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21350505329) 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, 1186139176 + ... + 1186139193.

Almost surely, 2^21350505321 is an apocalyptic number.

It is an amenable number.

21350505321 is a deficient number, since it is larger than the sum of its proper divisors (9489113489).

21350505321 is a wasteful number, since it uses less digits than its factorization.

21350505321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2372278375 (or 2372278372 counting only the distinct ones).

The product of its (nonzero) digits is 4500, while the sum is 27.

Subtracting from 21350505321 its reverse (12350505312), we obtain a palindrome (9000000009).

The spelling of 21350505321 in words is "twenty-one billion, three hundred fifty million, five hundred five thousand, three hundred twenty-one".