398051993 has 4 divisors (see below), whose sum is σ = 400957620. Its totient is φ = 395146368.

The previous prime is 398051987. The next prime is 398052001. The reversal of 398051993 is 399150893.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 399150893 = 229 ⋅1743017.

It can be written as a sum of positive squares in 2 ways, for example, as 274664329 + 123387664 = 16573^2 + 11108^2 .

It is a cyclic number.

It is not a de Polignac number, because 398051993 - 2¹⁴ = 398035609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (398051933) 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, 1452608 + ... + 1452881.

It is an arithmetic number, because the mean of its divisors is an integer number (100239405).

Almost surely, 2^398051993 is an apocalyptic number.

It is an amenable number.

398051993 is a deficient number, since it is larger than the sum of its proper divisors (2905627).

398051993 is a wasteful number, since it uses less digits than its factorization.

398051993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2905626.

The product of its (nonzero) digits is 262440, while the sum is 47.

The square root of 398051993 is about 19951.2403875047. The cubic root of 398051993 is about 735.6082662790.

The spelling of 398051993 in words is "three hundred ninety-eight million, fifty-one thousand, nine hundred ninety-three".