685731049 has 4 divisors (see below), whose sum is σ = 692388736. Its totient is φ = 679073364.

The previous prime is 685731043. The next prime is 685731061. The reversal of 685731049 is 940137586.

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, and also an emirpimes, since its reverse is a distinct semiprime: 940137586 = 2 ⋅470068793.

It is a cyclic number.

It is not a de Polignac number, because 685731049 - 2²⁹ = 148860137 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 685730996 and 685731014.

It is not an unprimeable number, because it can be changed into a prime (685731043) 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, 3328689 + ... + 3328894.

It is an arithmetic number, because the mean of its divisors is an integer number (173097184).

Almost surely, 2^685731049 is an apocalyptic number.

It is an amenable number.

685731049 is a deficient number, since it is larger than the sum of its proper divisors (6657687).

685731049 is a wasteful number, since it uses less digits than its factorization.

685731049 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6657686.

The product of its (nonzero) digits is 181440, while the sum is 43.

The square root of 685731049 is about 26186.4669056366. The cubic root of 685731049 is about 881.8294623687.

The spelling of 685731049 in words is "six hundred eighty-five million, seven hundred thirty-one thousand, forty-nine".