640228042664 has 64 divisors (see below), whose sum is σ = 1404860941440. Its totient is φ = 267804149760.

The previous prime is 640228042661. The next prime is 640228042679. The reversal of 640228042664 is 466240822046.

It is a super-2 number, since 2×640228042664² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (640228042661) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3179612 + ... + 3374964.

It is an arithmetic number, because the mean of its divisors is an integer number (21950952210).

Almost surely, 2^640228042664 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640228042664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (702430470720).

640228042664 is an abundant number, since it is smaller than the sum of its proper divisors (764632898776).

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

640228042664 is a wasteful number, since it uses less digits than its factorization.

640228042664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 196770 (or 196766 counting only the distinct ones).

The product of its (nonzero) digits is 884736, while the sum is 44.

The spelling of 640228042664 in words is "six hundred forty billion, two hundred twenty-eight million, forty-two thousand, six hundred sixty-four".