640701670 has 32 divisors (see below), whose sum is σ = 1350167616. Its totient is φ = 214310400.

The previous prime is 640701653. The next prime is 640701671. The reversal of 640701670 is 76107046.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640701671) 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 in 15 ways as a sum of consecutive naturals, for example, 108751 + ... + 114490.

It is an arithmetic number, because the mean of its divisors is an integer number (42192738).

Almost surely, 2^640701670 is an apocalyptic number.

640701670 is an abundant number, since it is smaller than the sum of its proper divisors (709465946).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

640701670 is a wasteful number, since it uses less digits than its factorization.

640701670 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 223296.

The product of its (nonzero) digits is 7056, while the sum is 31.

The square root of 640701670 is about 25312.0854533956. The cubic root of 640701670 is about 862.0886989438.

The spelling of 640701670 in words is "six hundred forty million, seven hundred one thousand, six hundred seventy".