640499201672 has 108 divisors (see below), whose sum is σ = 1368668247765. Its totient is φ = 280779920960.

The previous prime is 640499201669. The next prime is 640499201689. The reversal of 640499201672 is 276102994046.

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 640118405476 + 380796196 = 800074^2 + 19514^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=565906.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 640499201672.

It is an unprimeable number.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 722095613 + ... + 722096499.

Almost surely, 2^640499201672 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 640499201672

640499201672 is an abundant number, since it is smaller than the sum of its proper divisors (728169046093).

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

640499201672 is an equidigital number, since it uses as much as digits as its factorization.

640499201672 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1860 (or 929 counting only the distinct ones).

The product of its (nonzero) digits is 1306368, while the sum is 50.

Multiplying 640499201672 by its sum of digits (50), we get a square (32024960083600 = 5659060²).

The spelling of 640499201672 in words is "six hundred forty billion, four hundred ninety-nine million, two hundred one thousand, six hundred seventy-two".