640701697 has 8 divisors (see below), whose sum is σ = 656413056. Its totient is φ = 625077072.

The previous prime is 640701671. The next prime is 640701703. The reversal of 640701697 is 796107046.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 640701697 - 2⁷ = 640701569 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640701497) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6603 + ... + 36400.

It is an arithmetic number, because the mean of its divisors is an integer number (82051632).

Almost surely, 2^640701697 is an apocalyptic number.

It is an amenable number.

640701697 is a deficient number, since it is larger than the sum of its proper divisors (15711359).

640701697 is a wasteful number, since it uses less digits than its factorization.

640701697 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43367.

The product of its (nonzero) digits is 63504, while the sum is 40.

The square root of 640701697 is about 25312.0859867376. The cubic root of 640701697 is about 862.0887110536.

The spelling of 640701697 in words is "six hundred forty million, seven hundred one thousand, six hundred ninety-seven".