640701 has 12 divisors (see below), whose sum is σ = 932412. Its totient is φ = 423936.

The previous prime is 640691. The next prime is 640727. The reversal of 640701 is 107046.

It can be written as a sum of positive squares in 2 ways, for example, as 416025 + 224676 = 645^2 + 474^2 .

It is not a de Polignac number, because 640701 - 2⁵ = 640669 is a prime.

It is an Ulam number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 640701.

It is not an unprimeable number, because it can be changed into a prime (640741) 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, 2175 + ... + 2451.

It is an arithmetic number, because the mean of its divisors is an integer number (77701).

2⁶⁴⁰⁷⁰¹ is an apocalyptic number.

It is an amenable number.

640701 is a deficient number, since it is larger than the sum of its proper divisors (291711).

640701 is a wasteful number, since it uses less digits than its factorization.

640701 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 540 (or 537 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 18.

The square root of 640701 is about 800.4380050947. The cubic root of 640701 is about 86.2088398440.

Adding to 640701 its reverse (107046), we get a palindrome (747747).

The spelling of 640701 in words is "six hundred forty thousand, seven hundred one".