396991 has 4 divisors (see below), whose sum is σ = 453712. Its totient is φ = 340272.

The previous prime is 396983. The next prime is 396997. The reversal of 396991 is 199693.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 199693 = 13 ⋅15361.

It is a cyclic number.

It is not a de Polignac number, because 396991 - 2³ = 396983 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 396991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (396997) 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, 28350 + ... + 28363.

It is an arithmetic number, because the mean of its divisors is an integer number (113428).

2³⁹⁶⁹⁹¹ is an apocalyptic number.

396991 is a deficient number, since it is larger than the sum of its proper divisors (56721).

396991 is an equidigital number, since it uses as much as digits as its factorization.

396991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56720.

The product of its digits is 13122, while the sum is 37.

The square root of 396991 is about 630.0722180830. The cubic root of 396991 is about 73.4954105762.

The spelling of 396991 in words is "three hundred ninety-six thousand, nine hundred ninety-one".