640700733 has 4 divisors (see below), whose sum is σ = 854267648. Its totient is φ = 427133820.

The previous prime is 640700717. The next prime is 640700737. The reversal of 640700733 is 337007046.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 640700733 - 2⁴ = 640700717 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 640700733.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640700737) 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 3 ways as a sum of consecutive naturals, for example, 106783453 + ... + 106783458.

It is an arithmetic number, because the mean of its divisors is an integer number (213566912).

Almost surely, 2^640700733 is an apocalyptic number.

It is an amenable number.

640700733 is a deficient number, since it is larger than the sum of its proper divisors (213566915).

640700733 is a wasteful number, since it uses less digits than its factorization.

640700733 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 213566914.

The product of its (nonzero) digits is 10584, while the sum is 30.

The square root of 640700733 is about 25312.0669444437. The cubic root of 640700733 is about 862.0882786871.

Adding to 640700733 its reverse (337007046), we get a palindrome (977707779).

The spelling of 640700733 in words is "six hundred forty million, seven hundred thousand, seven hundred thirty-three".