8610721 has 12 divisors (see below), whose sum is σ = 10606788. Its totient is φ = 6945792.

The previous prime is 8610659. The next prime is 8610731. The reversal of 8610721 is 1270168.

It can be written as a sum of positive squares in 2 ways, for example, as 3111696 + 5499025 = 1764^2 + 2345^2 .

It is not a de Polignac number, because 8610721 - 2⁹ = 8610209 is a prime.

It is a super-4 number, since 4×8610721⁴ (a number of 29 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8610731) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4336 + ... + 6001.

It is an arithmetic number, because the mean of its divisors is an integer number (883899).

Almost surely, 2^8610721 is an apocalyptic number.

It is an amenable number.

8610721 is a deficient number, since it is larger than the sum of its proper divisors (1996067).

8610721 is a wasteful number, since it uses less digits than its factorization.

8610721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10368 (or 10361 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 25.

The square root of 8610721 is about 2934.4030057237. The cubic root of 8610721 is about 204.9650624577.

Adding to 8610721 its reverse (1270168), we get a palindrome (9880889).

The spelling of 8610721 in words is "eight million, six hundred ten thousand, seven hundred twenty-one".