21221305235 has 16 divisors (see below), whose sum is σ = 28616825664. Its totient is φ = 14989763712.

The previous prime is 21221305229. The next prime is 21221305247. The reversal of 21221305235 is 53250312212.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21221305235 - 2¹⁸ = 21221043091 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7095932 + ... + 7098921.

It is an arithmetic number, because the mean of its divisors is an integer number (1788551604).

Almost surely, 2^21221305235 is an apocalyptic number.

21221305235 is a deficient number, since it is larger than the sum of its proper divisors (7395520429).

21221305235 is a wasteful number, since it uses less digits than its factorization.

21221305235 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14194894.

The product of its (nonzero) digits is 3600, while the sum is 26.

Adding to 21221305235 its reverse (53250312212), we get a palindrome (74471617447).

The spelling of 21221305235 in words is "twenty-one billion, two hundred twenty-one million, three hundred five thousand, two hundred thirty-five".