21115515506359 has 2 divisors, whose sum is σ = 21115515506360. Its totient is φ = 21115515506358.

The previous prime is 21115515506357. The next prime is 21115515506369. The reversal of 21115515506359 is 95360551551112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21115515506359 - 2¹ = 21115515506357 is a prime.

Together with 21115515506357, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21115515506357) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10557757753179 + 10557757753180.

It is an arithmetic number, because the mean of its divisors is an integer number (10557757753180).

Almost surely, 2^{21115515506359} is an apocalyptic number.

21115515506359 is a deficient number, since it is larger than the sum of its proper divisors (1).

21115515506359 is an equidigital number, since it uses as much as digits as its factorization.

21115515506359 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1012500, while the sum is 49.

The spelling of 21115515506359 in words is "twenty-one trillion, one hundred fifteen billion, five hundred fifteen million, five hundred six thousand, three hundred fifty-nine".