21615410317 has 4 divisors (see below), whose sum is σ = 21638479996. Its totient is φ = 21592340640.

The previous prime is 21615410279. The next prime is 21615410339. The reversal of 21615410317 is 71301451612.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1773588996 + 19841821321 = 42114^2 + 140861^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21615410317 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21615410017) 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, 11533434 + ... + 11535307.

It is an arithmetic number, because the mean of its divisors is an integer number (5409619999).

Almost surely, 2^21615410317 is an apocalyptic number.

It is an amenable number.

21615410317 is a deficient number, since it is larger than the sum of its proper divisors (23069679).

21615410317 is an equidigital number, since it uses as much as digits as its factorization.

21615410317 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23069678.

The product of its (nonzero) digits is 5040, while the sum is 31.

Adding to 21615410317 its reverse (71301451612), we get a palindrome (92916861929).

The spelling of 21615410317 in words is "twenty-one billion, six hundred fifteen million, four hundred ten thousand, three hundred seventeen".