399228993 has 20 divisors (see below), whose sum is σ = 616947540. Its totient is φ = 256973472.

The previous prime is 399228979. The next prime is 399228997. The reversal of 399228993 is 399822993.

It can be written as a sum of positive squares in 2 ways, for example, as 64448784 + 334780209 = 8028^2 + 18297^2 .

It is not a de Polignac number, because 399228993 - 2¹⁸ = 398966849 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (399228997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 82630 + ... + 87327.

It is an arithmetic number, because the mean of its divisors is an integer number (30847377).

Almost surely, 2^399228993 is an apocalyptic number.

It is an amenable number.

399228993 is a deficient number, since it is larger than the sum of its proper divisors (217718547).

399228993 is a wasteful number, since it uses less digits than its factorization.

399228993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 169998 (or 169989 counting only the distinct ones).

The product of its digits is 1889568, while the sum is 54.

The square root of 399228993 is about 19980.7155277282. The cubic root of 399228993 is about 736.3325928926.

The spelling of 399228993 in words is "three hundred ninety-nine million, two hundred twenty-eight thousand, nine hundred ninety-three".