21215771115017 has 4 divisors (see below), whose sum is σ = 21290738504400. Its totient is φ = 21140803725636.

The previous prime is 21215771114987. The next prime is 21215771115031. The reversal of 21215771115017 is 71051117751212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21215771115017 - 2⁶ = 21215771114953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21215771145017) 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, 37483694267 + ... + 37483694832.

It is an arithmetic number, because the mean of its divisors is an integer number (5322684626100).

Almost surely, 2^{21215771115017} is an apocalyptic number.

It is an amenable number.

21215771115017 is a deficient number, since it is larger than the sum of its proper divisors (74967389383).

21215771115017 is an equidigital number, since it uses as much as digits as its factorization.

21215771115017 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74967389382.

The product of its (nonzero) digits is 34300, while the sum is 41.

Adding to 21215771115017 its reverse (71051117751212), we get a palindrome (92266888866229).

The spelling of 21215771115017 in words is "twenty-one trillion, two hundred fifteen billion, seven hundred seventy-one million, one hundred fifteen thousand, seventeen".