8985721 has 2 divisors, whose sum is σ = 8985722. Its totient is φ = 8985720.

The previous prime is 8985719. The next prime is 8985733. The reversal of 8985721 is 1275898.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8202496 + 783225 = 2864^2 + 885^2 .

It is a cyclic number.

It is not a de Polignac number, because 8985721 - 2¹ = 8985719 is a prime.

Together with 8985719, it forms a pair of twin primes.

It is an Ulam number.

It is not a weakly prime, because it can be changed into another prime (8985751) 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 as a sum of consecutive naturals, namely, 4492860 + 4492861.

It is an arithmetic number, because the mean of its divisors is an integer number (4492861).

Almost surely, 2^8985721 is an apocalyptic number.

It is an amenable number.

8985721 is a deficient number, since it is larger than the sum of its proper divisors (1).

8985721 is an equidigital number, since it uses as much as digits as its factorization.

8985721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 40320, while the sum is 40.

The square root of 8985721 is about 2997.6192219827. The cubic root of 8985721 is about 207.8983184590.

The spelling of 8985721 in words is "eight million, nine hundred eighty-five thousand, seven hundred twenty-one".