21000329617 has 2 divisors, whose sum is σ = 21000329618. Its totient is φ = 21000329616.

The previous prime is 21000329611. The next prime is 21000329621. The reversal of 21000329617 is 71692300012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17081444416 + 3918885201 = 130696^2 + 62601^2 .

It is a cyclic number.

It is not a de Polignac number, because 21000329617 - 2⁷ = 21000329489 is a prime.

It is not a weakly prime, because it can be changed into another prime (21000329611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500164808 + 10500164809.

It is an arithmetic number, because the mean of its divisors is an integer number (10500164809).

Almost surely, 2^21000329617 is an apocalyptic number.

It is an amenable number.

21000329617 is a deficient number, since it is larger than the sum of its proper divisors (1).

21000329617 is an equidigital number, since it uses as much as digits as its factorization.

21000329617 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4536, while the sum is 31.

Adding to 21000329617 its reverse (71692300012), we get a palindrome (92692629629).

The spelling of 21000329617 in words is "twenty-one billion, three hundred twenty-nine thousand, six hundred seventeen".