6520511765 has 4 divisors (see below), whose sum is σ = 7824614124. Its totient is φ = 5216409408.

The previous prime is 6520511761. The next prime is 6520511779. The reversal of 6520511765 is 5671150256.

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 3582980164 + 2937531601 = 59858^2 + 54199^2 .

It is a cyclic number.

It is not a de Polignac number, because 6520511765 - 2² = 6520511761 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 (6520511761) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 652051172 + ... + 652051181.

It is an arithmetic number, because the mean of its divisors is an integer number (1956153531).

Almost surely, 2^6520511765 is an apocalyptic number.

It is an amenable number.

6520511765 is a deficient number, since it is larger than the sum of its proper divisors (1304102359).

6520511765 is a wasteful number, since it uses less digits than its factorization.

6520511765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1304102358.

The product of its (nonzero) digits is 63000, while the sum is 38.

The square root of 6520511765 is about 80749.6858507821. The cubic root of 6520511765 is about 1868.2166040456.

The spelling of 6520511765 in words is "six billion, five hundred twenty million, five hundred eleven thousand, seven hundred sixty-five".