21553105017 has 4 divisors (see below), whose sum is σ = 28737473360. Its totient is φ = 14368736676.

The previous prime is 21553104977. The next prime is 21553105039. The reversal of 21553105017 is 71050135512.

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 21553105017 - 2¹¹ = 21553102969 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21513105017) 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, 3592184167 + ... + 3592184172.

It is an arithmetic number, because the mean of its divisors is an integer number (7184368340).

Almost surely, 2^21553105017 is an apocalyptic number.

It is an amenable number.

21553105017 is a deficient number, since it is larger than the sum of its proper divisors (7184368343).

21553105017 is an equidigital number, since it uses as much as digits as its factorization.

21553105017 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7184368342.

The product of its (nonzero) digits is 5250, while the sum is 30.

The spelling of 21553105017 in words is "twenty-one billion, five hundred fifty-three million, one hundred five thousand, seventeen".