685197871 has 4 divisors (see below), whose sum is σ = 691484200. Its totient is φ = 678911544.

The previous prime is 685197847. The next prime is 685197881. The reversal of 685197871 is 178791586.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 178791586 = 2 ⋅89395793.

It is a cyclic number.

It is not a de Polignac number, because 685197871 - 2¹³ = 685189679 is a prime.

It is a super-2 number, since 2×685197871² = 938992244845865282, 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 (685197881) 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, 3143001 + ... + 3143218.

It is an arithmetic number, because the mean of its divisors is an integer number (172871050).

Almost surely, 2^685197871 is an apocalyptic number.

685197871 is a deficient number, since it is larger than the sum of its proper divisors (6286329).

685197871 is a wasteful number, since it uses less digits than its factorization.

685197871 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6286328.

The product of its digits is 846720, while the sum is 52.

The square root of 685197871 is about 26176.2845148046. The cubic root of 685197871 is about 881.6008528284.

The spelling of 685197871 in words is "six hundred eighty-five million, one hundred ninety-seven thousand, eight hundred seventy-one".