640422240768 has 90 divisors (see below), whose sum is σ = 1848458743989. Its totient is φ = 213455972352.

The previous prime is 640422240763. The next prime is 640422240803. The reversal of 640422240768 is 867042224046.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It can be written as a sum of positive squares in 2 ways, for example, as 426712045824 + 213710194944 = 653232^2 + 462288^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=565872.

It is a super-2 number, since 2×640422240768² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (640422240763) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 54317818 + ... + 54329606.

Almost surely, 2^640422240768 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 640422240768

640422240768 is an abundant number, since it is smaller than the sum of its proper divisors (1208036503221).

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

640422240768 is an frugal number, since it uses more digits than its factorization.

640422240768 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23602 (or 11794 counting only the distinct ones).

The product of its (nonzero) digits is 1032192, while the sum is 45.

The spelling of 640422240768 in words is "six hundred forty billion, four hundred twenty-two million, two hundred forty thousand, seven hundred sixty-eight".