9913788896521 has 2 divisors, whose sum is σ = 9913788896522. Its totient is φ = 9913788896520.

The previous prime is 9913788896507. The next prime is 9913788896569. The reversal of 9913788896521 is 1256988873199.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9569964983296 + 343823913225 = 3093536^2 + 586365^2 .

It is a cyclic number.

It is not a de Polignac number, because 9913788896521 - 2⁹ = 9913788896009 is a prime.

It is not a weakly prime, because it can be changed into another prime (9913788896591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4956894448260 + 4956894448261.

It is an arithmetic number, because the mean of its divisors is an integer number (4956894448261).

Almost surely, 2^{9913788896521} is an apocalyptic number.

It is an amenable number.

9913788896521 is a deficient number, since it is larger than the sum of its proper divisors (1).

9913788896521 is an equidigital number, since it uses as much as digits as its factorization.

9913788896521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 470292480, while the sum is 76.

The spelling of 9913788896521 in words is "nine trillion, nine hundred thirteen billion, seven hundred eighty-eight million, eight hundred ninety-six thousand, five hundred twenty-one".