640604089 has 2 divisors, whose sum is σ = 640604090. Its totient is φ = 640604088.

The previous prime is 640604087. The next prime is 640604143. The reversal of 640604089 is 980406046.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 640090000 + 514089 = 25300^2 + 717^2 .

It is a cyclic number.

It is not a de Polignac number, because 640604089 - 2¹ = 640604087 is a prime.

Together with 640604087, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (640604087) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320302044 + 320302045.

It is an arithmetic number, because the mean of its divisors is an integer number (320302045).

Almost surely, 2^640604089 is an apocalyptic number.

It is an amenable number.

640604089 is a deficient number, since it is larger than the sum of its proper divisors (1).

640604089 is an equidigital number, since it uses as much as digits as its factorization.

640604089 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 41472, while the sum is 37.

The square root of 640604089 is about 25310.1578225028. The cubic root of 640604089 is about 862.0449303942.

The spelling of 640604089 in words is "six hundred forty million, six hundred four thousand, eighty-nine".