640186534 has 12 divisors (see below), whose sum is σ = 1039830156. Its totient is φ = 295470552.

The previous prime is 640186529. The next prime is 640186559. The reversal of 640186534 is 435681046.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 640186493 and 640186502.

It is a congruent number.

It is an unprimeable number.

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 5 ways as a sum of consecutive naturals, for example, 946684 + ... + 947359.

It is an arithmetic number, because the mean of its divisors is an integer number (86652513).

Almost surely, 2^640186534 is an apocalyptic number.

640186534 is a deficient number, since it is larger than the sum of its proper divisors (399643622).

640186534 is a wasteful number, since it uses less digits than its factorization.

640186534 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1894071 (or 1894058 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 37.

The square root of 640186534 is about 25301.9077146369. The cubic root of 640186534 is about 861.8575919051.

The spelling of 640186534 in words is "six hundred forty million, one hundred eighty-six thousand, five hundred thirty-four".