640765089 has 12 divisors (see below), whose sum is σ = 926058276. Its totient is φ = 426941952.

The previous prime is 640765087. The next prime is 640765093. The reversal of 640765089 is 980567046.

It can be written as a sum of positive squares in 2 ways, for example, as 432972864 + 207792225 = 20808^2 + 14415^2 .

It is not a de Polignac number, because 640765089 - 2¹ = 640765087 is a prime.

It is not an unprimeable number, because it can be changed into a prime (640765087) 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, 1392 + ... + 35825.

It is an arithmetic number, because the mean of its divisors is an integer number (77171523).

Almost surely, 2^640765089 is an apocalyptic number.

It is an amenable number.

640765089 is a deficient number, since it is larger than the sum of its proper divisors (285293187).

640765089 is a wasteful number, since it uses less digits than its factorization.

640765089 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39136 (or 39133 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 45.

The square root of 640765089 is about 25313.3381639009. The cubic root of 640765089 is about 862.1171422386.

The spelling of 640765089 in words is "six hundred forty million, seven hundred sixty-five thousand, eighty-nine".