21433320553 has 4 divisors (see below), whose sum is σ = 21433655440. Its totient is φ = 21432985668.

The previous prime is 21433320529. The next prime is 21433320577. The reversal of 21433320553 is 35502333412.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (21433320529) and next prime (21433320577).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21433320553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21433320583) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 38175 + ... + 210532.

It is an arithmetic number, because the mean of its divisors is an integer number (5358413860).

Almost surely, 2^21433320553 is an apocalyptic number.

It is an amenable number.

21433320553 is a deficient number, since it is larger than the sum of its proper divisors (334887).

21433320553 is an equidigital number, since it uses as much as digits as its factorization.

21433320553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 334886.

The product of its (nonzero) digits is 32400, while the sum is 31.

Adding to 21433320553 its reverse (35502333412), we get a palindrome (56935653965).

The spelling of 21433320553 in words is "twenty-one billion, four hundred thirty-three million, three hundred twenty thousand, five hundred fifty-three".