640265540220 has 144 divisors (see below), whose sum is σ = 2007336965088. Its totient is φ = 165064573440.

The previous prime is 640265540219. The next prime is 640265540221. The reversal of 640265540220 is 22045562046.

640265540220 is a `hidden beast` number, since 64 + 0 + 26 + 554 + 0 + 2 + 20 = 666.

It is an interprime number because it is at equal distance from previous prime (640265540219) and next prime (640265540221).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640265540221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 739455 + ... + 1351785.

Almost surely, 2^640265540220 is an apocalyptic number.

640265540220 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640265540220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1003668482544).

640265540220 is an abundant number, since it is smaller than the sum of its proper divisors (1367071424868).

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

640265540220 is a wasteful number, since it uses less digits than its factorization.

640265540220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 612540 (or 612535 counting only the distinct ones).

The product of its (nonzero) digits is 115200, while the sum is 36.

The spelling of 640265540220 in words is "six hundred forty billion, two hundred sixty-five million, five hundred forty thousand, two hundred twenty".