393399857 has 8 divisors (see below), whose sum is σ = 398514600. Its totient is φ = 388312704.

The previous prime is 393399841. The next prime is 393399887. The reversal of 393399857 is 758993393.

It can be written as a sum of positive squares in 4 ways, for example, as 10962721 + 382437136 = 3311^2 + 19556^2 .

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 393399857 - 2⁴ = 393399841 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (393399887) 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, 22613 + ... + 36029.

It is an arithmetic number, because the mean of its divisors is an integer number (49814325).

Almost surely, 2^393399857 is an apocalyptic number.

It is an amenable number.

393399857 is a deficient number, since it is larger than the sum of its proper divisors (5114743).

393399857 is a wasteful number, since it uses less digits than its factorization.

393399857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13795.

The product of its digits is 5511240, while the sum is 56.

The square root of 393399857 is about 19834.3100963961. The cubic root of 393399857 is about 732.7312813217.

The spelling of 393399857 in words is "three hundred ninety-three million, three hundred ninety-nine thousand, eight hundred fifty-seven".