9721531 has 4 divisors (see below), whose sum is σ = 9786064. Its totient is φ = 9657000.

The previous prime is 9721529. The next prime is 9721561. The reversal of 9721531 is 1351279.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 9721531 - 2¹ = 9721529 is a prime.

It is a super-2 number, since 2×9721531² = 189016329967922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 9721531.

It is not an unprimeable number, because it can be changed into a prime (9721511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32040 + ... + 32341.

It is an arithmetic number, because the mean of its divisors is an integer number (2446516).

Almost surely, 2^9721531 is an apocalyptic number.

9721531 is a deficient number, since it is larger than the sum of its proper divisors (64533).

9721531 is a wasteful number, since it uses less digits than its factorization.

9721531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64532.

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

The square root of 9721531 is about 3117.9369781957. The cubic root of 9721531 is about 213.4248026269.

The spelling of 9721531 in words is "nine million, seven hundred twenty-one thousand, five hundred thirty-one".