9008721 has 6 divisors (see below), whose sum is σ = 13012610. Its totient is φ = 6005808.

The previous prime is 9008707. The next prime is 9008731. The reversal of 9008721 is 1278009.

It can be written as a sum of positive squares in only one way, i.e., 7290000 + 1718721 = 2700^2 + 1311^2 .

It is a de Polignac number, because none of the positive numbers 2^k-9008721 is a prime.

It is a Duffinian number.

It is a Curzon number.

9008721 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (9008731) 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 5 ways as a sum of consecutive naturals, for example, 500476 + ... + 500493.

Almost surely, 2^9008721 is an apocalyptic number.

It is an amenable number.

9008721 is a deficient number, since it is larger than the sum of its proper divisors (4003889).

9008721 is a wasteful number, since it uses less digits than its factorization.

9008721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1000975 (or 1000972 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 27.

The square root of 9008721 is about 3001.4531480601. The cubic root of 9008721 is about 208.0755473230.

The spelling of 9008721 in words is "nine million, eight thousand, seven hundred twenty-one".