21450103553 has 4 divisors (see below), whose sum is σ = 21452289540. Its totient is φ = 21447917568.

The previous prime is 21450103471. The next prime is 21450103567. The reversal of 21450103553 is 35530105412.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 16275890929 + 5174212624 = 127577^2 + 71932^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21450103553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21450103253) 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, 1078208 + ... + 1097921.

It is an arithmetic number, because the mean of its divisors is an integer number (5363072385).

Almost surely, 2^21450103553 is an apocalyptic number.

It is an amenable number.

21450103553 is a deficient number, since it is larger than the sum of its proper divisors (2185987).

21450103553 is an equidigital number, since it uses as much as digits as its factorization.

21450103553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2185986.

The product of its (nonzero) digits is 9000, while the sum is 29.

Adding to 21450103553 its reverse (35530105412), we get a palindrome (56980208965).

The spelling of 21450103553 in words is "twenty-one billion, four hundred fifty million, one hundred three thousand, five hundred fifty-three".