396640 has 48 divisors (see below), whose sum is σ = 976752. Its totient is φ = 152064.

The previous prime is 396637. The next prime is 396647. The reversal of 396640 is 46693.

It is a junction number, because it is equal to n+sod(n) for n = 396599 and 396608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (396647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5887 + ... + 5953.

It is an arithmetic number, because the mean of its divisors is an integer number (20349).

2³⁹⁶⁶⁴⁰ 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 396640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (488376).

396640 is an abundant number, since it is smaller than the sum of its proper divisors (580112).

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

396640 is a wasteful number, since it uses less digits than its factorization.

396640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 119 (or 111 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 28.

The square root of 396640 is about 629.7936169889. The cubic root of 396640 is about 73.4737438418.

The spelling of 396640 in words is "three hundred ninety-six thousand, six hundred forty".