684405940 has 48 divisors (see below), whose sum is σ = 1505589120. Its totient is φ = 260839040.

The previous prime is 684405923. The next prime is 684405961. The reversal of 684405940 is 49504486.

It is a super-2 number, since 2×684405940² = 936822981414567200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 684405893 and 684405902.

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, 120975 + ... + 126505.

It is an arithmetic number, because the mean of its divisors is an integer number (31366440).

Almost surely, 2^684405940 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 684405940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (752794560).

684405940 is an abundant number, since it is smaller than the sum of its proper divisors (821183180).

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

684405940 is a wasteful number, since it uses less digits than its factorization.

684405940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5832 (or 5830 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 40.

The square root of 684405940 is about 26161.1532620410. The cubic root of 684405940 is about 881.2610793503.

The spelling of 684405940 in words is "six hundred eighty-four million, four hundred five thousand, nine hundred forty".