640291437 has 12 divisors (see below), whose sum is σ = 926147040. Its totient is φ = 426269448.

The previous prime is 640291433. The next prime is 640291459. The reversal of 640291437 is 734192046.

640291437 is a `hidden beast` number, since 640 + 2 + 9 + 1 + 4 + 3 + 7 = 666.

It is not a de Polignac number, because 640291437 - 2² = 640291433 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640291433) 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 11 ways as a sum of consecutive naturals, for example, 42387 + ... + 55472.

It is an arithmetic number, because the mean of its divisors is an integer number (77178920).

Almost surely, 2^640291437 is an apocalyptic number.

It is an amenable number.

640291437 is a deficient number, since it is larger than the sum of its proper divisors (285855603).

640291437 is a wasteful number, since it uses less digits than its factorization.

640291437 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 98592 (or 98589 counting only the distinct ones).

The product of its (nonzero) digits is 36288, while the sum is 36.

The square root of 640291437 is about 25303.9806552250. The cubic root of 640291437 is about 861.9046649087.

The spelling of 640291437 in words is "six hundred forty million, two hundred ninety-one thousand, four hundred thirty-seven".