21505055500499 has 2 divisors, whose sum is σ = 21505055500500. Its totient is φ = 21505055500498.

The previous prime is 21505055500493. The next prime is 21505055500507. The reversal of 21505055500499 is 99400555050512.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21505055500499 - 2⁴ = 21505055500483 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (21505055500493) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10752527750249 + 10752527750250.

It is an arithmetic number, because the mean of its divisors is an integer number (10752527750250).

Almost surely, 2^{21505055500499} is an apocalyptic number.

21505055500499 is a deficient number, since it is larger than the sum of its proper divisors (1).

21505055500499 is an equidigital number, since it uses as much as digits as its factorization.

21505055500499 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2025000, while the sum is 50.

The spelling of 21505055500499 in words is "twenty-one trillion, five hundred five billion, fifty-five million, five hundred thousand, four hundred ninety-nine".