685507940 has 48 divisors (see below), whose sum is σ = 1559575920. Its totient is φ = 253094400.

The previous prime is 685507937. The next prime is 685507969. The reversal of 685507940 is 49705586.

It can be written as a sum of positive squares in 8 ways, for example, as 337163044 + 348344896 = 18362^2 + 18664^2 .

It is a super-2 number, since 2×685507940² = 939842271606087200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 685507891 and 685507900.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 36140 + ... + 51740.

It is an arithmetic number, because the mean of its divisors is an integer number (32491165).

Almost surely, 2^685507940 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 685507940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (779787960).

685507940 is an abundant number, since it is smaller than the sum of its proper divisors (874067980).

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

685507940 is a wasteful number, since it uses less digits than its factorization.

685507940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15649 (or 15621 counting only the distinct ones).

The product of its (nonzero) digits is 302400, while the sum is 44.

The square root of 685507940 is about 26182.2065533064. The cubic root of 685507940 is about 881.7338148447.

The spelling of 685507940 in words is "six hundred eighty-five million, five hundred seven thousand, nine hundred forty".