640256656342 has 16 divisors (see below), whose sum is σ = 970547296320. Its totient is φ = 316742669568.

The previous prime is 640256656331. The next prime is 640256656343. The reversal of 640256656342 is 243656652046.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640256656343) 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 7 ways as a sum of consecutive naturals, for example, 280284 + ... + 1165792.

It is an arithmetic number, because the mean of its divisors is an integer number (60659206020).

Almost surely, 2^640256656342 is an apocalyptic number.

640256656342 is a deficient number, since it is larger than the sum of its proper divisors (330290639978).

640256656342 is a wasteful number, since it uses less digits than its factorization.

640256656342 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 889335.

The product of its (nonzero) digits is 6220800, while the sum is 49.

The spelling of 640256656342 in words is "six hundred forty billion, two hundred fifty-six million, six hundred fifty-six thousand, three hundred forty-two".