21504218757079 has 2 divisors, whose sum is σ = 21504218757080. Its totient is φ = 21504218757078.

The previous prime is 21504218757071. The next prime is 21504218757173. The reversal of 21504218757079 is 97075781240512.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21504218757079 - 2³ = 21504218757071 is a prime.

It is a super-2 number, since 2×21504218757079² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21504218757071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10752109378539 + 10752109378540.

It is an arithmetic number, because the mean of its divisors is an integer number (10752109378540).

Almost surely, 2^{21504218757079} is an apocalyptic number.

21504218757079 is a deficient number, since it is larger than the sum of its proper divisors (1).

21504218757079 is an equidigital number, since it uses as much as digits as its factorization.

21504218757079 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9878400, while the sum is 58.

The spelling of 21504218757079 in words is "twenty-one trillion, five hundred four billion, two hundred eighteen million, seven hundred fifty-seven thousand, seventy-nine".