397840757 has 4 divisors (see below), whose sum is σ = 400475616. Its totient is φ = 395205900.

The previous prime is 397840741. The next prime is 397840771. The reversal of 397840757 is 757048793.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 397840757 - 2⁴ = 397840741 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 (397840727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1317203 + ... + 1317504.

It is an arithmetic number, because the mean of its divisors is an integer number (100118904).

Almost surely, 2^397840757 is an apocalyptic number.

It is an amenable number.

397840757 is a deficient number, since it is larger than the sum of its proper divisors (2634859).

397840757 is a wasteful number, since it uses less digits than its factorization.

397840757 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2634858.

The product of its (nonzero) digits is 1481760, while the sum is 50.

The square root of 397840757 is about 19945.9458787995. The cubic root of 397840757 is about 735.4781204310.

The spelling of 397840757 in words is "three hundred ninety-seven million, eight hundred forty thousand, seven hundred fifty-seven".