21567482009 has 2 divisors, whose sum is σ = 21567482010. Its totient is φ = 21567482008.

The previous prime is 21567481967. The next prime is 21567482047. The reversal of 21567482009 is 90028476512.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19437936400 + 2129545609 = 139420^2 + 46147^2 .

It is a cyclic number.

It is not a de Polignac number, because 21567482009 - 2¹⁶ = 21567416473 is a prime.

It is not a weakly prime, because it can be changed into another prime (21567481009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10783741004 + 10783741005.

It is an arithmetic number, because the mean of its divisors is an integer number (10783741005).

Almost surely, 2^21567482009 is an apocalyptic number.

It is an amenable number.

21567482009 is a deficient number, since it is larger than the sum of its proper divisors (1).

21567482009 is an equidigital number, since it uses as much as digits as its factorization.

21567482009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 241920, while the sum is 44.

The spelling of 21567482009 in words is "twenty-one billion, five hundred sixty-seven million, four hundred eighty-two thousand, nine".