684590640 has 80 divisors (see below), whose sum is σ = 2147862528. Its totient is φ = 180352768.

The previous prime is 684590611. The next prime is 684590651. The reversal of 684590640 is 46095486.

It is a tau number, because it is divible by the number of its divisors (80).

It is a junction number, because it is equal to n+sod(n) for n = 684590592 and 684590601.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2737 + ... + 37103.

Almost surely, 2^684590640 is an apocalyptic number.

684590640 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 684590640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1073931264).

684590640 is an abundant number, since it is smaller than the sum of its proper divisors (1463271888).

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

684590640 is a wasteful number, since it uses less digits than its factorization.

684590640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34466 (or 34460 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 42.

The square root of 684590640 is about 26164.6830670658. The cubic root of 684590640 is about 881.3403472584.

The spelling of 684590640 in words is "six hundred eighty-four million, five hundred ninety thousand, six hundred forty".