397909 has 4 divisors (see below), whose sum is σ = 411660. Its totient is φ = 384160.

The previous prime is 397907. The next prime is 397921. The reversal of 397909 is 909793.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 142884 + 255025 = 378^2 + 505^2 .

It is a cyclic number.

It is not a de Polignac number, because 397909 - 2¹ = 397907 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (397907) 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, 6832 + ... + 6889.

It is an arithmetic number, because the mean of its divisors is an integer number (102915).

2³⁹⁷⁹⁰⁹ is an apocalyptic number.

It is an amenable number.

397909 is a deficient number, since it is larger than the sum of its proper divisors (13751).

397909 is a wasteful number, since it uses less digits than its factorization.

397909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13750.

The product of its (nonzero) digits is 15309, while the sum is 37.

The square root of 397909 is about 630.8002853519. The cubic root of 397909 is about 73.5520171061.

The spelling of 397909 in words is "three hundred ninety-seven thousand, nine hundred nine".