6440640533 has 4 divisors (see below), whose sum is σ = 6440811648. Its totient is φ = 6440469420.

The previous prime is 6440640529. The next prime is 6440640571. The reversal of 6440640533 is 3350460446.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 3350460446 = 2 ⋅1675230223.

It is a cyclic number.

It is not a de Polignac number, because 6440640533 - 2² = 6440640529 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 6440640493 and 6440640502.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6440640523) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1703 + ... + 113508.

It is an arithmetic number, because the mean of its divisors is an integer number (1610202912).

Almost surely, 2^6440640533 is an apocalyptic number.

It is an amenable number.

6440640533 is a deficient number, since it is larger than the sum of its proper divisors (171115).

6440640533 is a wasteful number, since it uses less digits than its factorization.

6440640533 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 171114.

The product of its (nonzero) digits is 103680, while the sum is 35.

The square root of 6440640533 is about 80253.6013709042. The cubic root of 6440640533 is about 1860.5571742932.

The spelling of 6440640533 in words is "six billion, four hundred forty million, six hundred forty thousand, five hundred thirty-three".