640570745 has 4 divisors (see below), whose sum is σ = 768684900. Its totient is φ = 512456592.

The previous prime is 640570739. The next prime is 640570747. The reversal of 640570745 is 547075046.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 253701184 + 386869561 = 15928^2 + 19669^2 .

It is a cyclic number.

It is not a de Polignac number, because 640570745 - 2⁶ = 640570681 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 640570699 and 640570708.

It is not an unprimeable number, because it can be changed into a prime (640570747) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64057070 + ... + 64057079.

It is an arithmetic number, because the mean of its divisors is an integer number (192171225).

Almost surely, 2^640570745 is an apocalyptic number.

It is an amenable number.

640570745 is a deficient number, since it is larger than the sum of its proper divisors (128114155).

640570745 is a wasteful number, since it uses less digits than its factorization.

640570745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128114154.

The product of its (nonzero) digits is 117600, while the sum is 38.

The square root of 640570745 is about 25309.4991060669. The cubic root of 640570745 is about 862.0299734052.

The spelling of 640570745 in words is "six hundred forty million, five hundred seventy thousand, seven hundred forty-five".