640536423 has 8 divisors (see below), whose sum is σ = 854489328. Its totient is φ = 426803904.

The previous prime is 640536419. The next prime is 640536439. The reversal of 640536423 is 324635046.

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

It is not a de Polignac number, because 640536423 - 2² = 640536419 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640536443) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 48190 + ... + 60027.

It is an arithmetic number, because the mean of its divisors is an integer number (106811166).

Almost surely, 2^640536423 is an apocalyptic number.

640536423 is a deficient number, since it is larger than the sum of its proper divisors (213952905).

640536423 is a wasteful number, since it uses less digits than its factorization.

640536423 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110193.

The product of its (nonzero) digits is 51840, while the sum is 33.

The square root of 640536423 is about 25308.8210511671. The cubic root of 640536423 is about 862.0145771764.

The spelling of 640536423 in words is "six hundred forty million, five hundred thirty-six thousand, four hundred twenty-three".