685127405 has 4 divisors (see below), whose sum is σ = 822152892. Its totient is φ = 548101920.

The previous prime is 685127383. The next prime is 685127423. The reversal of 685127405 is 504721586.

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 109223401 + 575904004 = 10451^2 + 23998^2 .

It is a de Polignac number, because none of the positive numbers 2^k-685127405 is a prime.

It is a super-2 number, since 2×685127405² = 938799122164068050, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 68512736 + ... + 68512745.

It is an arithmetic number, because the mean of its divisors is an integer number (205538223).

Almost surely, 2^685127405 is an apocalyptic number.

It is an amenable number.

685127405 is a deficient number, since it is larger than the sum of its proper divisors (137025487).

685127405 is a wasteful number, since it uses less digits than its factorization.

685127405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137025486.

The product of its (nonzero) digits is 67200, while the sum is 38.

The square root of 685127405 is about 26174.9384908542. The cubic root of 685127405 is about 881.5706304074.

The spelling of 685127405 in words is "six hundred eighty-five million, one hundred twenty-seven thousand, four hundred five".