9897513721 has 8 divisors (see below), whose sum is σ = 10006814664. Its totient is φ = 9788593920.

The previous prime is 9897513707. The next prime is 9897513737. The reversal of 9897513721 is 1273157989.

9897513721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 934158096 + 8963355625 = 30564^2 + 94675^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 9897513721 - 2¹⁵ = 9897480953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (9897513121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 42906 + ... + 147091.

It is an arithmetic number, because the mean of its divisors is an integer number (1250851833).

Almost surely, 2^9897513721 is an apocalyptic number.

It is an amenable number.

9897513721 is a deficient number, since it is larger than the sum of its proper divisors (109300943).

9897513721 is a wasteful number, since it uses less digits than its factorization.

9897513721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 190571.

The product of its digits is 952560, while the sum is 52.

The square root of 9897513721 is about 99486.2489040571. The cubic root of 9897513721 is about 2147.0494027642.

The spelling of 9897513721 in words is "nine billion, eight hundred ninety-seven million, five hundred thirteen thousand, seven hundred twenty-one".