397781 has 4 divisors (see below), whose sum is σ = 404364. Its totient is φ = 391200.

The previous prime is 397763. The next prime is 397799. The reversal of 397781 is 187793.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (397763) and next prime (397799).

It can be written as a sum of positive squares in 2 ways, for example, as 180625 + 217156 = 425^2 + 466^2 .

It is a cyclic number.

It is not a de Polignac number, because 397781 - 2¹⁸ = 135637 is a prime.

It is a super-3 number, since 3×397781³ = 188822333480791623, which contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (397721) 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, 3200 + ... + 3321.

It is an arithmetic number, because the mean of its divisors is an integer number (101091).

2³⁹⁷⁷⁸¹ is an apocalyptic number.

It is an amenable number.

397781 is a deficient number, since it is larger than the sum of its proper divisors (6583).

397781 is an equidigital number, since it uses as much as digits as its factorization.

397781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6582.

The product of its digits is 10584, while the sum is 35.

The square root of 397781 is about 630.6988187717. The cubic root of 397781 is about 73.5441294837.

The spelling of 397781 in words is "three hundred ninety-seven thousand, seven hundred eighty-one".