399424993 has 12 divisors (see below), whose sum is σ = 449751204. Its totient is φ = 354252800.

The previous prime is 399424981. The next prime is 399424999.

399424993 is nontrivially palindromic in base 10.

It can be written as a sum of positive squares in 2 ways, for example, as 8690704 + 390734289 = 2948^2 + 19767^2 .

It is not a de Polignac number, because 399424993 - 2⁹ = 399424481 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 399424993.

It is not an unprimeable number, because it can be changed into a prime (399424999) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 35296 + ... + 45217.

It is an arithmetic number, because the mean of its divisors is an integer number (37479267).

Almost surely, 2^399424993 is an apocalyptic number.

It is an amenable number.

399424993 is a deficient number, since it is larger than the sum of its proper divisors (50326211).

399424993 is a wasteful number, since it uses less digits than its factorization.

399424993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80576 (or 80565 counting only the distinct ones).

The product of its digits is 1889568, while the sum is 52.

The square root of 399424993 is about 19985.6196551420. The cubic root of 399424993 is about 736.4530731008.

It can be divided in two parts, 39942 and 4993, that multiplied together give a triangular number (199430406 = T₁₉₉₇₁).

The spelling of 399424993 in words is "three hundred ninety-nine million, four hundred twenty-four thousand, nine hundred ninety-three".