281873981 has 8 divisors (see below), whose sum is σ = 287675064. Its totient is φ = 276090880.

The previous prime is 281873959. The next prime is 281873989. The reversal of 281873981 is 189378182.

It can be written as a sum of positive squares in 4 ways, for example, as 221563225 + 60310756 = 14885^2 + 7766^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-281873981 is a prime.

It is a super-2 number, since 2×281873981² = 158905882329576722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (281873989) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 29825 + ... + 38121.

It is an arithmetic number, because the mean of its divisors is an integer number (35959383).

Almost surely, 2^281873981 is an apocalyptic number.

It is an amenable number.

281873981 is a deficient number, since it is larger than the sum of its proper divisors (5801083).

281873981 is an equidigital number, since it uses as much as digits as its factorization.

281873981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8991.

The product of its digits is 193536, while the sum is 47.

The square root of 281873981 is about 16789.1030433433. The cubic root of 281873981 is about 655.6695218770.

The spelling of 281873981 in words is "two hundred eighty-one million, eight hundred seventy-three thousand, nine hundred eighty-one".