8612721 has 12 divisors (see below), whose sum is σ = 13397748. Its totient is φ = 5300064.

The previous prime is 8612713. The next prime is 8612729. The reversal of 8612721 is 1272168.

8612721 is digitally balanced in base 2, base 3 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (8612713) and next prime (8612729).

It can be written as a sum of positive squares in 2 ways, for example, as 2852721 + 5760000 = 1689^2 + 2400^2 .

It is not a de Polignac number, because 8612721 - 2³ = 8612713 is a prime.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (8612729) 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, 36690 + ... + 36923.

It is an arithmetic number, because the mean of its divisors is an integer number (1116479).

Almost surely, 2^8612721 is an apocalyptic number.

It is an amenable number.

8612721 is a deficient number, since it is larger than the sum of its proper divisors (4785027).

8612721 is a wasteful number, since it uses less digits than its factorization.

8612721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73632 (or 73629 counting only the distinct ones).

The product of its digits is 1344, while the sum is 27.

The square root of 8612721 is about 2934.7437707575. The cubic root of 8612721 is about 204.9809302110.

Adding to 8612721 its reverse (1272168), we get a palindrome (9884889).

The spelling of 8612721 in words is "eight million, six hundred twelve thousand, seven hundred twenty-one".