21563007217 has 16 divisors (see below), whose sum is σ = 22728401280. Its totient is φ = 20428531200.

The previous prime is 21563007211. The next prime is 21563007239. The reversal of 21563007217 is 71270036512.

It is a cyclic number.

It is not a de Polignac number, because 21563007217 - 2²⁷ = 21428789489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21563007211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 409633 + ... + 459265.

It is an arithmetic number, because the mean of its divisors is an integer number (1420525080).

Almost surely, 2^21563007217 is an apocalyptic number.

It is an amenable number.

21563007217 is a deficient number, since it is larger than the sum of its proper divisors (1165394063).

21563007217 is a wasteful number, since it uses less digits than its factorization.

21563007217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49944.

The product of its (nonzero) digits is 17640, while the sum is 34.

The spelling of 21563007217 in words is "twenty-one billion, five hundred sixty-three million, seven thousand, two hundred seventeen".