640088437 has 4 divisors (see below), whose sum is σ = 677740716. Its totient is φ = 602436160.

The previous prime is 640088431. The next prime is 640088461. The reversal of 640088437 is 734880046.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 397165041 + 242923396 = 19929^2 + 15586^2 .

It is a cyclic number.

It is not a de Polignac number, because 640088437 - 2³ = 640088429 is a prime.

It is a super-2 number, since 2×640088437² = 819426414362205938, which contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

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 640088437.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640088431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18826114 + ... + 18826147.

It is an arithmetic number, because the mean of its divisors is an integer number (169435179).

Almost surely, 2^640088437 is an apocalyptic number.

It is an amenable number.

640088437 is a deficient number, since it is larger than the sum of its proper divisors (37652279).

640088437 is a wasteful number, since it uses less digits than its factorization.

640088437 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37652278.

The product of its (nonzero) digits is 129024, while the sum is 40.

The square root of 640088437 is about 25299.9691106531. The cubic root of 640088437 is about 861.8135682972.

The spelling of 640088437 in words is "six hundred forty million, eighty-eight thousand, four hundred thirty-seven".