640653461406 has 128 divisors (see below), whose sum is σ = 1710193858560. Its totient is φ = 173807099136.

The previous prime is 640653461381. The next prime is 640653461407. The reversal of 640653461406 is 604164356046.

640653461406 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-4 number, since 4×640653461406⁴ (a number of 48 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640653461407) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 922140 + ... + 1460016.

It is an arithmetic number, because the mean of its divisors is an integer number (13360889520).

Almost surely, 2^640653461406 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640653461406, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (855096929280).

640653461406 is an abundant number, since it is smaller than the sum of its proper divisors (1069540397154).

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

640653461406 is a wasteful number, since it uses less digits than its factorization.

640653461406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 538055 (or 538049 counting only the distinct ones).

The product of its (nonzero) digits is 1244160, while the sum is 45.

The spelling of 640653461406 in words is "six hundred forty billion, six hundred fifty-three million, four hundred sixty-one thousand, four hundred six".