6520713557 has 4 divisors (see below), whose sum is σ = 6539397900. Its totient is φ = 6502029216.

The previous prime is 6520713553. The next prime is 6520713559. The reversal of 6520713557 is 7553170256.

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 5284417636 + 1236295921 = 72694^2 + 35161^2 .

It is a cyclic number.

It is not a de Polignac number, because 6520713557 - 2² = 6520713553 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 (6520713553) 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, 9341648 + ... + 9342345.

It is an arithmetic number, because the mean of its divisors is an integer number (1634849475).

Almost surely, 2^6520713557 is an apocalyptic number.

It is an amenable number.

6520713557 is a deficient number, since it is larger than the sum of its proper divisors (18684343).

6520713557 is a wasteful number, since it uses less digits than its factorization.

6520713557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18684342.

The product of its (nonzero) digits is 220500, while the sum is 41.

The square root of 6520713557 is about 80750.9353320443. The cubic root of 6520713557 is about 1868.2358759110.

The spelling of 6520713557 in words is "six billion, five hundred twenty million, seven hundred thirteen thousand, five hundred fifty-seven".