640975702 has 4 divisors (see below), whose sum is σ = 961463556. Its totient is φ = 320487850.

The previous prime is 640975681. The next prime is 640975703. The reversal of 640975702 is 207579046.

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

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640975703) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160243924 + ... + 160243927.

It is an arithmetic number, because the mean of its divisors is an integer number (240365889).

Almost surely, 2^640975702 is an apocalyptic number.

640975702 is a deficient number, since it is larger than the sum of its proper divisors (320487854).

640975702 is a wasteful number, since it uses less digits than its factorization.

640975702 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 320487853.

The product of its (nonzero) digits is 105840, while the sum is 40.

The square root of 640975702 is about 25317.4979411473. The cubic root of 640975702 is about 862.2115882847.

The spelling of 640975702 in words is "six hundred forty million, nine hundred seventy-five thousand, seven hundred two".