397681 has 8 divisors (see below), whose sum is σ = 426600. Its totient is φ = 369408.

The previous prime is 397673. The next prime is 397687. The reversal of 397681 is 186793.

It can be written as a sum of positive squares in 4 ways, for example, as 18225 + 379456 = 135^2 + 616^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 397681 - 2³ = 397673 is a prime.

It is a super-2 number, since 2×397681² = 316300355522, which contains 22 as substring.

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 (397687) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2455 + ... + 2611.

It is an arithmetic number, because the mean of its divisors is an integer number (53325).

2³⁹⁷⁶⁸¹ is an apocalyptic number.

It is an amenable number.

397681 is a deficient number, since it is larger than the sum of its proper divisors (28919).

397681 is a wasteful number, since it uses less digits than its factorization.

397681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 323.

The product of its digits is 9072, while the sum is 34.

The square root of 397681 is about 630.6195366463. The cubic root of 397681 is about 73.5379661012.

The spelling of 397681 in words is "three hundred ninety-seven thousand, six hundred eighty-one".