685651720 has 64 divisors (see below), whose sum is σ = 1677049920. Its totient is φ = 250777344.

The previous prime is 685651693. The next prime is 685651723. The reversal of 685651720 is 27156586.

It is a super-2 number, since 2×685651720² = 940236562277916800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is not an unprimeable number, because it can be changed into a prime (685651723) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 49479 + ... + 61801.

It is an arithmetic number, because the mean of its divisors is an integer number (26203905).

Almost surely, 2^685651720 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 685651720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (838524960).

685651720 is an abundant number, since it is smaller than the sum of its proper divisors (991398200).

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

685651720 is a wasteful number, since it uses less digits than its factorization.

685651720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12454 (or 12450 counting only the distinct ones).

The product of its (nonzero) digits is 100800, while the sum is 40.

The square root of 685651720 is about 26184.9521672276. The cubic root of 685651720 is about 881.7954561563.

The spelling of 685651720 in words is "six hundred eighty-five million, six hundred fifty-one thousand, seven hundred twenty".