21033305553 has 16 divisors (see below), whose sum is σ = 30206433600. Its totient is φ = 12941530944.

The previous prime is 21033305551. The next prime is 21033305567. The reversal of 21033305553 is 35550333012.

It is not a de Polignac number, because 21033305553 - 2¹ = 21033305551 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21033305553.

It is not an unprimeable number, because it can be changed into a prime (21033305551) by changing a digit.

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, 229975 + ... + 308147.

It is an arithmetic number, because the mean of its divisors is an integer number (1887902100).

Almost surely, 2^21033305553 is an apocalyptic number.

It is an amenable number.

21033305553 is a deficient number, since it is larger than the sum of its proper divisors (9173128047).

21033305553 is a wasteful number, since it uses less digits than its factorization.

21033305553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85088.

The product of its (nonzero) digits is 20250, while the sum is 30.

Adding to 21033305553 its reverse (35550333012), we get a palindrome (56583638565).

The spelling of 21033305553 in words is "twenty-one billion, thirty-three million, three hundred five thousand, five hundred fifty-three".