640720227544 has 16 divisors (see below), whose sum is σ = 1229288809320. Its totient is φ = 312909878400.

The previous prime is 640720227527. The next prime is 640720227551. The reversal of 640720227544 is 445722027046.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (43).

It is a self number, because there is not a number n which added to its sum of digits gives 640720227544.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 931279057 + ... + 931279744.

Almost surely, 2^640720227544 is an apocalyptic number.

It is an amenable number.

640720227544 is a deficient number, since it is larger than the sum of its proper divisors (588568581776).

640720227544 is a wasteful number, since it uses less digits than its factorization.

640720227544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1862558850 (or 1862558846 counting only the distinct ones).

The product of its (nonzero) digits is 752640, while the sum is 43.

The spelling of 640720227544 in words is "six hundred forty billion, seven hundred twenty million, two hundred twenty-seven thousand, five hundred forty-four".