685782107521 has 4 divisors (see below), whose sum is σ = 783750980032. Its totient is φ = 587813235012.

The previous prime is 685782107519. The next prime is 685782107567. The reversal of 685782107521 is 125701287586.

685782107521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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.

It is a cyclic number.

It is not a de Polignac number, because 685782107521 - 2¹ = 685782107519 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (685782107321) 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, 48984436245 + ... + 48984436258.

It is an arithmetic number, because the mean of its divisors is an integer number (195937745008).

Almost surely, 2^685782107521 is an apocalyptic number.

It is an amenable number.

685782107521 is a deficient number, since it is larger than the sum of its proper divisors (97968872511).

685782107521 is an equidigital number, since it uses as much as digits as its factorization.

685782107521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97968872510.

The product of its (nonzero) digits is 1881600, while the sum is 52.

The spelling of 685782107521 in words is "six hundred eighty-five billion, seven hundred eighty-two million, one hundred seven thousand, five hundred twenty-one".