21221535303555 has 32 divisors (see below), whose sum is σ = 34071832279296. Its totient is φ = 11279030281344.

The previous prime is 21221535303541. The next prime is 21221535303571. The reversal of 21221535303555 is 55530353512212.

It is not a de Polignac number, because 21221535303555 - 2⁹ = 21221535303043 is a prime.

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 31 ways as a sum of consecutive naturals, for example, 114542224 + ... + 114727346.

It is an arithmetic number, because the mean of its divisors is an integer number (1064744758728).

Almost surely, 2^{21221535303555} is an apocalyptic number.

21221535303555 is a deficient number, since it is larger than the sum of its proper divisors (12850296975741).

21221535303555 is a wasteful number, since it uses less digits than its factorization.

21221535303555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 211507.

The product of its (nonzero) digits is 675000, while the sum is 42.

Adding to 21221535303555 its reverse (55530353512212), we get a palindrome (76751888815767).

The spelling of 21221535303555 in words is "twenty-one trillion, two hundred twenty-one billion, five hundred thirty-five million, three hundred three thousand, five hundred fifty-five".