685021440 has 288 divisors, whose sum is σ = 2369404800. Its totient is φ = 168099840.

The previous prime is 685021439. The next prime is 685021451. The reversal of 685021440 is 44120586.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 685021398 and 685021407.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2991246 + ... + 2991474.

It is an arithmetic number, because the mean of its divisors is an integer number (8227100).

Almost surely, 2^685021440 is an apocalyptic number.

685021440 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 685021440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1184702400).

685021440 is an abundant number, since it is smaller than the sum of its proper divisors (1684383360).

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

685021440 is a wasteful number, since it uses less digits than its factorization.

685021440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 313 (or 299 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 30.

The square root of 685021440 is about 26172.9142435458. The cubic root of 685021440 is about 881.5251787889.

The spelling of 685021440 in words is "six hundred eighty-five million, twenty-one thousand, four hundred forty".