9721513 has 2 divisors, whose sum is σ = 9721514. Its totient is φ = 9721512.

The previous prime is 9721511. The next prime is 9721519. The reversal of 9721513 is 3151279.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6492304 + 3229209 = 2548^2 + 1797^2 .

It is a cyclic number.

It is not a de Polignac number, because 9721513 - 2¹ = 9721511 is a prime.

Together with 9721511, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (9721511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4860756 + 4860757.

It is an arithmetic number, because the mean of its divisors is an integer number (4860757).

Almost surely, 2^9721513 is an apocalyptic number.

It is an amenable number.

9721513 is a deficient number, since it is larger than the sum of its proper divisors (1).

9721513 is an equidigital number, since it uses as much as digits as its factorization.

9721513 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1890, while the sum is 28.

The square root of 9721513 is about 3117.9340916703. The cubic root of 9721513 is about 213.4246709039.

It can be divided in two parts, 972 and 1513, that added together give a triangular number (2485 = T₇₀).

The spelling of 9721513 in words is "nine million, seven hundred twenty-one thousand, five hundred thirteen".