640518425 has 24 divisors (see below), whose sum is σ = 808635000. Its totient is φ = 503193600.

The previous prime is 640518419. The next prime is 640518449. The reversal of 640518425 is 524815046.

It can be written as a sum of positive squares in 12 ways, for example, as 124456336 + 516062089 = 11156^2 + 22717^2 .

It is not a de Polignac number, because 640518425 - 2¹⁰ = 640517401 is a prime.

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 23 ways as a sum of consecutive naturals, for example, 512201 + ... + 513449.

It is an arithmetic number, because the mean of its divisors is an integer number (33693125).

Almost surely, 2^640518425 is an apocalyptic number.

It is an amenable number.

640518425 is a deficient number, since it is larger than the sum of its proper divisors (168116575).

640518425 is a wasteful number, since it uses less digits than its factorization.

640518425 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1613 (or 1608 counting only the distinct ones).

The product of its (nonzero) digits is 38400, while the sum is 35.

The square root of 640518425 is about 25308.4654809414. The cubic root of 640518425 is about 862.0065033792.

The spelling of 640518425 in words is "six hundred forty million, five hundred eighteen thousand, four hundred twenty-five".