21359684553 has 4 divisors (see below), whose sum is σ = 28479579408. Its totient is φ = 14239789700.

The previous prime is 21359684503. The next prime is 21359684557. The reversal of 21359684553 is 35548695312.

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 a cyclic number.

It is not a de Polignac number, because 21359684553 - 2¹⁰ = 21359683529 is a prime.

It is a super-2 number, since 2×21359684553² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21359684496 and 21359684505.

It is not an unprimeable number, because it can be changed into a prime (21359684557) 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 3 ways as a sum of consecutive naturals, for example, 3559947423 + ... + 3559947428.

It is an arithmetic number, because the mean of its divisors is an integer number (7119894852).

Almost surely, 2^21359684553 is an apocalyptic number.

It is an amenable number.

21359684553 is a deficient number, since it is larger than the sum of its proper divisors (7119894855).

21359684553 is an equidigital number, since it uses as much as digits as its factorization.

21359684553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7119894854.

The product of its digits is 3888000, while the sum is 51.

The spelling of 21359684553 in words is "twenty-one billion, three hundred fifty-nine million, six hundred eighty-four thousand, five hundred fifty-three".