393689 has 4 divisors (see below), whose sum is σ = 399156. Its totient is φ = 388224.

The previous prime is 393683. The next prime is 393697. The reversal of 393689 is 986393.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 986393 = 97 ⋅10169.

It can be written as a sum of positive squares in 2 ways, for example, as 313600 + 80089 = 560^2 + 283^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-393689 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (393683) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2624 + ... + 2769.

It is an arithmetic number, because the mean of its divisors is an integer number (99789).

2³⁹³⁶⁸⁹ is an apocalyptic number.

It is an amenable number.

393689 is a deficient number, since it is larger than the sum of its proper divisors (5467).

393689 is an equidigital number, since it uses as much as digits as its factorization.

393689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5466.

The product of its digits is 34992, while the sum is 38.

The square root of 393689 is about 627.4464120544. The cubic root of 393689 is about 73.2910752863.

Subtracting 393689 from its reverse (986393), we obtain a cube (592704 = 84³).

The spelling of 393689 in words is "three hundred ninety-three thousand, six hundred eighty-nine".