393940 has 12 divisors (see below), whose sum is σ = 827316. Its totient is φ = 157568.

The previous prime is 393931. The next prime is 393947. The reversal of 393940 is 49393.

393940 = 155² + 156² + ... + 169².

It can be written as a sum of positive squares in 2 ways, for example, as 93636 + 300304 = 306^2 + 548^2 .

It is a junction number, because it is equal to n+sod(n) for n = 393899 and 393908.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (393947) 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 3 ways as a sum of consecutive naturals, for example, 9829 + ... + 9868.

It is an arithmetic number, because the mean of its divisors is an integer number (68943).

2³⁹³⁹⁴⁰ is an apocalyptic number.

It is an amenable number.

393940 is an abundant number, since it is smaller than the sum of its proper divisors (433376).

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

393940 is a wasteful number, since it uses less digits than its factorization.

393940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19706 (or 19704 counting only the distinct ones).

The product of its (nonzero) digits is 2916, while the sum is 28.

The square root of 393940 is about 627.6463972652. The cubic root of 393940 is about 73.3066477744.

The spelling of 393940 in words is "three hundred ninety-three thousand, nine hundred forty".