685221768 has 320 divisors, whose sum is σ = 2475601920. Its totient is φ = 171849600.

The previous prime is 685221749. The next prime is 685221787. The reversal of 685221768 is 867122586.

685221768 is a `hidden beast` number, since 68 + 522 + 1 + 7 + 68 = 666.

685221768 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (685221749) and next prime (685221787).

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 1546555 + ... + 1546997.

It is an arithmetic number, because the mean of its divisors is an integer number (7736256).

Almost surely, 2^685221768 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 685221768, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1237800960).

685221768 is an abundant number, since it is smaller than the sum of its proper divisors (1790380152).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

685221768 is a wasteful number, since it uses less digits than its factorization.

685221768 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 510 (or 497 counting only the distinct ones).

The product of its digits is 322560, while the sum is 45.

The square root of 685221768 is about 26176.7409736201. The cubic root of 685221768 is about 881.6111016297.

The spelling of 685221768 in words is "six hundred eighty-five million, two hundred twenty-one thousand, seven hundred sixty-eight".