21115515030321 has 16 divisors (see below), whose sum is σ = 28205021104704. Its totient is φ = 14051513309184.

The previous prime is 21115515030271. The next prime is 21115515030343. The reversal of 21115515030321 is 12303051551112.

It is not a de Polignac number, because 21115515030321 - 2²⁵ = 21115481475889 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21115515032321) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21950770 + ... + 22892516.

It is an arithmetic number, because the mean of its divisors is an integer number (1762813819044).

Almost surely, 2^{21115515030321} is an apocalyptic number.

It is an amenable number.

21115515030321 is a deficient number, since it is larger than the sum of its proper divisors (7089506074383).

21115515030321 is a wasteful number, since it uses less digits than its factorization.

21115515030321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 955280.

The product of its (nonzero) digits is 4500, while the sum is 30.

Adding to 21115515030321 its reverse (12303051551112), we get a palindrome (33418566581433).

The spelling of 21115515030321 in words is "twenty-one trillion, one hundred fifteen billion, five hundred fifteen million, thirty thousand, three hundred twenty-one".