21555005500579 has 4 divisors (see below), whose sum is σ = 21920344576920. Its totient is φ = 21189666424240.

The previous prime is 21555005500559. The next prime is 21555005500583. The reversal of 21555005500579 is 97500550055512.

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

It is a cyclic number.

It is not a de Polignac number, because 21555005500579 - 2³⁹ = 21005249686691 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21555005500549) 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, 182669538082 + ... + 182669538199.

It is an arithmetic number, because the mean of its divisors is an integer number (5480086144230).

Almost surely, 2^{21555005500579} is an apocalyptic number.

21555005500579 is a deficient number, since it is larger than the sum of its proper divisors (365339076341).

21555005500579 is an equidigital number, since it uses as much as digits as its factorization.

21555005500579 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 365339076340.

The product of its (nonzero) digits is 1968750, while the sum is 49.

The spelling of 21555005500579 in words is "twenty-one trillion, five hundred fifty-five billion, five million, five hundred thousand, five hundred seventy-nine".