8640905 has 24 divisors (see below), whose sum is σ = 12994632. Its totient is φ = 5467392.

The previous prime is 8640889. The next prime is 8640911. The reversal of 8640905 is 5090468.

It can be written as a sum of positive squares in 4 ways, for example, as 1713481 + 6927424 = 1309^2 + 2632^2 .

It is not a de Polignac number, because 8640905 - 2⁴ = 8640889 is a prime.

It is a congruent number.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 1829 + ... + 4541.

It is an arithmetic number, because the mean of its divisors is an integer number (541443).

Almost surely, 2^8640905 is an apocalyptic number.

It is an amenable number.

8640905 is a deficient number, since it is larger than the sum of its proper divisors (4353727).

8640905 is a wasteful number, since it uses less digits than its factorization.

8640905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2745 (or 2738 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 32.

The square root of 8640905 is about 2939.5416309350. The cubic root of 8640905 is about 205.2042778336.

The spelling of 8640905 in words is "eight million, six hundred forty thousand, nine hundred five".