281966393 has 4 divisors (see below), whose sum is σ = 282043428. Its totient is φ = 281889360.

The previous prime is 281966387. The next prime is 281966401. The reversal of 281966393 is 393669182.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 393669182 = 2 ⋅196834591.

It can be written as a sum of positive squares in 2 ways, for example, as 200732224 + 81234169 = 14168^2 + 9013^2 .

It is a cyclic number.

It is not a de Polignac number, because 281966393 - 2¹⁸ = 281704249 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (281966303) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32738 + ... + 40443.

It is an arithmetic number, because the mean of its divisors is an integer number (70510857).

Almost surely, 2^281966393 is an apocalyptic number.

It is an amenable number.

281966393 is a deficient number, since it is larger than the sum of its proper divisors (77035).

281966393 is an equidigital number, since it uses as much as digits as its factorization.

281966393 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77034.

The product of its digits is 419904, while the sum is 47.

The square root of 281966393 is about 16791.8549600692. The cubic root of 281966393 is about 655.7411675006.

The spelling of 281966393 in words is "two hundred eighty-one million, nine hundred sixty-six thousand, three hundred ninety-three".