21535460553 has 4 divisors (see below), whose sum is σ = 28713947408. Its totient is φ = 14356973700.

The previous prime is 21535460539. The next prime is 21535460633. The reversal of 21535460553 is 35506453512.

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 not a de Polignac number, because 21535460553 - 2⁴ = 21535460537 is a prime.

It is a super-2 number, since 2×21535460553² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21535460503) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3589243423 + ... + 3589243428.

It is an arithmetic number, because the mean of its divisors is an integer number (7178486852).

Almost surely, 2^21535460553 is an apocalyptic number.

It is an amenable number.

21535460553 is a deficient number, since it is larger than the sum of its proper divisors (7178486855).

21535460553 is an equidigital number, since it uses as much as digits as its factorization.

21535460553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7178486854.

The product of its (nonzero) digits is 270000, while the sum is 39.

The spelling of 21535460553 in words is "twenty-one billion, five hundred thirty-five million, four hundred sixty thousand, five hundred fifty-three".