640729543 has 8 divisors (see below), whose sum is σ = 651855600. Its totient is φ = 629623680.

The previous prime is 640729511. The next prime is 640729559. The reversal of 640729543 is 345927046.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 640729543 - 2⁵ = 640729511 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 640729496 and 640729505.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640729043) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 67983 + ... + 76831.

It is an arithmetic number, because the mean of its divisors is an integer number (81481950).

Almost surely, 2^640729543 is an apocalyptic number.

640729543 is a deficient number, since it is larger than the sum of its proper divisors (11126057).

640729543 is a wasteful number, since it uses less digits than its factorization.

640729543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10097.

The product of its (nonzero) digits is 181440, while the sum is 40.

The square root of 640729543 is about 25312.6360342024. The cubic root of 640729543 is about 862.1012001598.

The spelling of 640729543 in words is "six hundred forty million, seven hundred twenty-nine thousand, five hundred forty-three".