21221213535 has 12 divisors (see below), whose sum is σ = 36783436872. Its totient is φ = 11317980528.

The previous prime is 21221213513. The next prime is 21221213561. The reversal of 21221213535 is 53531212212.

21221213535 is a `hidden beast` number, since 2 + 1 + 2 + 2 + 121 + 3 + 535 = 666.

It is not a de Polignac number, because 21221213535 - 2⁹ = 21221213023 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21221213499 and 21221213508.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 235791217 + ... + 235791306.

It is an arithmetic number, because the mean of its divisors is an integer number (3065286406).

Almost surely, 2^21221213535 is an apocalyptic number.

21221213535 is a deficient number, since it is larger than the sum of its proper divisors (15562223337).

21221213535 is a wasteful number, since it uses less digits than its factorization.

21221213535 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 471582534 (or 471582531 counting only the distinct ones).

The product of its digits is 3600, while the sum is 27.

Adding to 21221213535 its reverse (53531212212), we get a palindrome (74752425747).

The spelling of 21221213535 in words is "twenty-one billion, two hundred twenty-one million, two hundred thirteen thousand, five hundred thirty-five".