21517226503247 has 4 divisors (see below), whose sum is σ = 21527556426840. Its totient is φ = 21506896579656.

The previous prime is 21517226503237. The next prime is 21517226503249. The reversal of 21517226503247 is 74230562271512.

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

It is a cyclic number.

It is not a de Polignac number, because 21517226503247 - 2¹⁶ = 21517226437711 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 (21517226503249) 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, 5164958672 + ... + 5164962837.

It is an arithmetic number, because the mean of its divisors is an integer number (5381889106710).

Almost surely, 2^{21517226503247} is an apocalyptic number.

21517226503247 is a deficient number, since it is larger than the sum of its proper divisors (10329923593).

21517226503247 is a wasteful number, since it uses less digits than its factorization.

21517226503247 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10329923592.

The product of its (nonzero) digits is 1411200, while the sum is 47.

Adding to 21517226503247 its reverse (74230562271512), we get a palindrome (95747788774759).

The spelling of 21517226503247 in words is "twenty-one trillion, five hundred seventeen billion, two hundred twenty-six million, five hundred three thousand, two hundred forty-seven".