685811279 has 4 divisors (see below), whose sum is σ = 687574680. Its totient is φ = 684047880.

The previous prime is 685811219. The next prime is 685811333. The reversal of 685811279 is 972118586.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 972118586 = 2 ⋅486059293.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-685811279 is a prime.

It is a super-2 number, since 2×685811279² = 940674220807231682, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (685811219) 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, 881117 + ... + 881894.

It is an arithmetic number, because the mean of its divisors is an integer number (171893670).

Almost surely, 2^685811279 is an apocalyptic number.

685811279 is a deficient number, since it is larger than the sum of its proper divisors (1763401).

685811279 is a wasteful number, since it uses less digits than its factorization.

685811279 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1763400.

The product of its digits is 241920, while the sum is 47.

The square root of 685811279 is about 26187.9987589735. The cubic root of 685811279 is about 881.8638521482.

The spelling of 685811279 in words is "six hundred eighty-five million, eight hundred eleven thousand, two hundred seventy-nine".