281981913 has 4 divisors (see below), whose sum is σ = 375975888. Its totient is φ = 187987940.

The previous prime is 281981893. The next prime is 281981923. The reversal of 281981913 is 319189182.

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 a cyclic number.

It is not a de Polignac number, because 281981913 - 2⁶ = 281981849 is a prime.

It is not an unprimeable number, because it can be changed into a prime (281981923) 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, 46996983 + ... + 46996988.

It is an arithmetic number, because the mean of its divisors is an integer number (93993972).

Almost surely, 2^281981913 is an apocalyptic number.

It is an amenable number.

281981913 is a deficient number, since it is larger than the sum of its proper divisors (93993975).

281981913 is an equidigital number, since it uses as much as digits as its factorization.

281981913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93993974.

The product of its digits is 31104, while the sum is 42.

The square root of 281981913 is about 16792.3170825232. The cubic root of 281981913 is about 655.7531983862.

The spelling of 281981913 in words is "two hundred eighty-one million, nine hundred eighty-one thousand, nine hundred thirteen".