685721823 has 8 divisors (see below), whose sum is σ = 916600368. Its totient is φ = 455995584.

The previous prime is 685721821. The next prime is 685721857. The reversal of 685721823 is 328127586.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 685721823 - 2¹ = 685721821 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (685721821) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 286686 + ... + 289067.

It is an arithmetic number, because the mean of its divisors is an integer number (114575046).

Almost surely, 2^685721823 is an apocalyptic number.

685721823 is a deficient number, since it is larger than the sum of its proper divisors (230878545).

685721823 is a wasteful number, since it uses less digits than its factorization.

685721823 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 576153.

The product of its digits is 161280, while the sum is 42.

The square root of 685721823 is about 26186.2907453499. The cubic root of 685721823 is about 881.8255075650.

It can be divided in two parts, 6857 and 21823, that added together give a triangular number (28680 = T₂₃₉).

The spelling of 685721823 in words is "six hundred eighty-five million, seven hundred twenty-one thousand, eight hundred twenty-three".