640390448238 has 64 divisors (see below), whose sum is σ = 1324458584064. Its totient is φ = 206309376000.

The previous prime is 640390448237. The next prime is 640390448263. The reversal of 640390448238 is 832844093046.

640390448238 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640390448233) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 27781998 + ... + 27805038.

It is an arithmetic number, because the mean of its divisors is an integer number (20694665376).

Almost surely, 2^640390448238 is an apocalyptic number.

640390448238 is an abundant number, since it is smaller than the sum of its proper divisors (684068135826).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

640390448238 is a wasteful number, since it uses less digits than its factorization.

640390448238 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24401.

The product of its (nonzero) digits is 3981312, while the sum is 51.

The spelling of 640390448238 in words is "six hundred forty billion, three hundred ninety million, four hundred forty-eight thousand, two hundred thirty-eight".