9721257 has 24 divisors (see below), whose sum is σ = 16240896. Its totient is φ = 5126688.

The previous prime is 9721247. The next prime is 9721273. The reversal of 9721257 is 7521279.

It is not a de Polignac number, because 9721257 - 2⁴ = 9721241 is a prime.

It is not an unprimeable number, because it can be changed into a prime (9721247) 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 in 23 ways as a sum of consecutive naturals, for example, 633 + ... + 4454.

It is an arithmetic number, because the mean of its divisors is an integer number (676704).

Almost surely, 2^9721257 is an apocalyptic number.

It is an amenable number.

9721257 is a deficient number, since it is larger than the sum of its proper divisors (6519639).

9721257 is a wasteful number, since it uses less digits than its factorization.

9721257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5117 (or 5110 counting only the distinct ones).

The product of its digits is 8820, while the sum is 33.

The square root of 9721257 is about 3117.8930385759. The cubic root of 9721257 is about 213.4227974920.

The spelling of 9721257 in words is "nine million, seven hundred twenty-one thousand, two hundred fifty-seven".