397805309 has 8 divisors (see below), whose sum is σ = 452837952. Its totient is φ = 345917440.

The previous prime is 397805297. The next prime is 397805323. The reversal of 397805309 is 903508793.

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

It is a de Polignac number, because none of the positive numbers 2^k-397805309 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 397805309.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (397805809) 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, 785924 + ... + 786429.

It is an arithmetic number, because the mean of its divisors is an integer number (56604744).

Almost surely, 2^397805309 is an apocalyptic number.

It is an amenable number.

397805309 is a deficient number, since it is larger than the sum of its proper divisors (55032643).

397805309 is a wasteful number, since it uses less digits than its factorization.

397805309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1572387.

The product of its (nonzero) digits is 204120, while the sum is 44.

The square root of 397805309 is about 19945.0572573758. The cubic root of 397805309 is about 735.4562758426.

The spelling of 397805309 in words is "three hundred ninety-seven million, eight hundred five thousand, three hundred nine".