6439564693 has 4 divisors (see below), whose sum is σ = 6613607020. Its totient is φ = 6265522368.

The previous prime is 6439564669. The next prime is 6439564709. The reversal of 6439564693 is 3964659346.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 6112425124 + 327139569 = 78182^2 + 18087^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6439564693 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6439564643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 87021108 + ... + 87021181.

It is an arithmetic number, because the mean of its divisors is an integer number (1653401755).

Almost surely, 2^6439564693 is an apocalyptic number.

It is an amenable number.

6439564693 is a deficient number, since it is larger than the sum of its proper divisors (174042327).

6439564693 is a wasteful number, since it uses less digits than its factorization.

6439564693 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 174042326.

The product of its digits is 12597120, while the sum is 55.

The square root of 6439564693 is about 80246.8983388143. The cubic root of 6439564693 is about 1860.4535731434.

The spelling of 6439564693 in words is "six billion, four hundred thirty-nine million, five hundred sixty-four thousand, six hundred ninety-three".