640700810 has 8 divisors (see below), whose sum is σ = 1153261476. Its totient is φ = 256280320.

The previous prime is 640700803. The next prime is 640700849. The reversal of 640700810 is 18007046.

It can be written as a sum of positive squares in 2 ways, for example, as 621455041 + 19245769 = 24929^2 + 4387^2 .

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

It is a super-2 number, since 2×640700810² = 820995055869312200, which contains 22 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 640700810.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32035031 + ... + 32035050.

Almost surely, 2^640700810 is an apocalyptic number.

640700810 is a deficient number, since it is larger than the sum of its proper divisors (512560666).

640700810 is a wasteful number, since it uses less digits than its factorization.

640700810 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64070088.

The product of its (nonzero) digits is 1344, while the sum is 26.

The square root of 640700810 is about 25312.0684654573. The cubic root of 640700810 is about 862.0883132226.

Adding to 640700810 its reverse (18007046), we get a palindrome (658707856).

The spelling of 640700810 in words is "six hundred forty million, seven hundred thousand, eight hundred ten".