640450501523 has 16 divisors (see below), whose sum is σ = 737344041984. Its totient is φ = 544907745600.

The previous prime is 640450501511. The next prime is 640450501553. The reversal of 640450501523 is 325105054046.

It is not a de Polignac number, because 640450501523 - 2⁸ = 640450501267 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640450501553) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20744048 + ... + 20774898.

It is an arithmetic number, because the mean of its divisors is an integer number (46084002624).

Almost surely, 2^640450501523 is an apocalyptic number.

640450501523 is a deficient number, since it is larger than the sum of its proper divisors (96893540461).

640450501523 is a wasteful number, since it uses less digits than its factorization.

640450501523 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52642.

The product of its (nonzero) digits is 72000, while the sum is 35.

Adding to 640450501523 its reverse (325105054046), we get a palindrome (965555555569).

The spelling of 640450501523 in words is "six hundred forty billion, four hundred fifty million, five hundred one thousand, five hundred twenty-three".