281613 has 4 divisors (see below), whose sum is σ = 375488. Its totient is φ = 187740.

The previous prime is 281609. The next prime is 281621. The reversal of 281613 is 316182.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 281613 - 2² = 281609 is a prime.

It is a D-number.

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 281613.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (281623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 46933 + ... + 46938.

It is an arithmetic number, because the mean of its divisors is an integer number (93872).

2²⁸¹⁶¹³ is an apocalyptic number.

It is an amenable number.

281613 is a deficient number, since it is larger than the sum of its proper divisors (93875).

281613 is an equidigital number, since it uses as much as digits as its factorization.

281613 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 93874.

The product of its digits is 288, while the sum is 21.

The square root of 281613 is about 530.6722152139. The cubic root of 281613 is about 65.5467102667.

Adding to 281613 its reverse (316182), we get a palindrome (597795).

The spelling of 281613 in words is "two hundred eighty-one thousand, six hundred thirteen".