9720581 has 4 divisors (see below), whose sum is σ = 10468332. Its totient is φ = 8972832.

The previous prime is 9720551. The next prime is 9720589. The reversal of 9720581 is 1850279.

9720581 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

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

It can be written as a sum of positive squares in 2 ways, for example, as 4268356 + 5452225 = 2066^2 + 2335^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-9720581 is a prime.

It is a super-2 number, since 2×9720581² = 188979389955122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9720589) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 373856 + ... + 373881.

It is an arithmetic number, because the mean of its divisors is an integer number (2617083).

Almost surely, 2^9720581 is an apocalyptic number.

It is an amenable number.

9720581 is a deficient number, since it is larger than the sum of its proper divisors (747751).

9720581 is a wasteful number, since it uses less digits than its factorization.

9720581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 747750.

The product of its (nonzero) digits is 5040, while the sum is 32.

The square root of 9720581 is about 3117.7846301501. The cubic root of 9720581 is about 213.4178503555.

It can be divided in two parts, 9720 and 581, that added together give a palindrome (10301).

The spelling of 9720581 in words is "nine million, seven hundred twenty thousand, five hundred eighty-one".