640340273540 has 96 divisors (see below), whose sum is σ = 1545182352000. Its totient is φ = 220451051520.

The previous prime is 640340273479. The next prime is 640340273549. The reversal of 640340273540 is 45372043046.

It is a Harshad number since it is a multiple of its sum of digits (38).

It is a junction number, because it is equal to n+sod(n) for n = 640340273494 and 640340273503.

It is not an unprimeable number, because it can be changed into a prime (640340273549) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6425372 + ... + 6524268.

It is an arithmetic number, because the mean of its divisors is an integer number (16095649500).

Almost surely, 2^640340273540 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 640340273540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (772591176000).

640340273540 is an abundant number, since it is smaller than the sum of its proper divisors (904842078460).

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

640340273540 is a wasteful number, since it uses less digits than its factorization.

640340273540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 100485 (or 100483 counting only the distinct ones).

The product of its (nonzero) digits is 241920, while the sum is 38.

The spelling of 640340273540 in words is "six hundred forty billion, three hundred forty million, two hundred seventy-three thousand, five hundred forty".