21231353306 has 4 divisors (see below), whose sum is σ = 31847029962. Its totient is φ = 10615676652.

The previous prime is 21231353279. The next prime is 21231353321. The reversal of 21231353306 is 60335313212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 20128515625 + 1102837681 = 141875^2 + 33209^2 .

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5307838325 + ... + 5307838328.

Almost surely, 2^21231353306 is an apocalyptic number.

21231353306 is a deficient number, since it is larger than the sum of its proper divisors (10615676656).

21231353306 is a wasteful number, since it uses less digits than its factorization.

21231353306 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10615676655.

The product of its (nonzero) digits is 9720, while the sum is 29.

Adding to 21231353306 its reverse (60335313212), we get a palindrome (81566666518).

The spelling of 21231353306 in words is "twenty-one billion, two hundred thirty-one million, three hundred fifty-three thousand, three hundred six".