640087433 has 8 divisors (see below), whose sum is σ = 649528488. Its totient is φ = 630664704.

The previous prime is 640087429. The next prime is 640087439. The reversal of 640087433 is 334780046.

640087433 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 3433609 + 636653824 = 1853^2 + 25232^2 .

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 640087433 - 2² = 640087429 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 640087393 and 640087402.

It is not an unprimeable number, because it can be changed into a prime (640087439) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 76085 + ... + 84077.

It is an arithmetic number, because the mean of its divisors is an integer number (81191061).

Almost surely, 2^640087433 is an apocalyptic number.

It is an amenable number.

640087433 is a deficient number, since it is larger than the sum of its proper divisors (9441055).

640087433 is a wasteful number, since it uses less digits than its factorization.

640087433 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9163.

The product of its (nonzero) digits is 48384, while the sum is 35.

The square root of 640087433 is about 25299.9492687238. The cubic root of 640087433 is about 861.8131177025.

The spelling of 640087433 in words is "six hundred forty million, eighty-seven thousand, four hundred thirty-three".