6685947509 has 4 divisors (see below), whose sum is σ = 6812097516. Its totient is φ = 6559797504.

The previous prime is 6685947497. The next prime is 6685947523. The reversal of 6685947509 is 9057495866.

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 5436112900 + 1249834609 = 73730^2 + 35353^2 .

It is a cyclic number.

It is not a de Polignac number, because 6685947509 - 2⁸ = 6685947253 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 (6685947589) 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, 63074924 + ... + 63075029.

It is an arithmetic number, because the mean of its divisors is an integer number (1703024379).

Almost surely, 2^6685947509 is an apocalyptic number.

It is an amenable number.

6685947509 is a deficient number, since it is larger than the sum of its proper divisors (126150007).

6685947509 is a wasteful number, since it uses less digits than its factorization.

6685947509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126150006.

The product of its (nonzero) digits is 16329600, while the sum is 59.

The square root of 6685947509 is about 81767.6434110706. The cubic root of 6685947509 is about 1883.8847081425.

The spelling of 6685947509 in words is "six billion, six hundred eighty-five million, nine hundred forty-seven thousand, five hundred nine".