281981389 has 2 divisors, whose sum is σ = 281981390. Its totient is φ = 281981388.

The previous prime is 281981383. The next prime is 281981393. The reversal of 281981389 is 983189182.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 279993289 + 1988100 = 16733^2 + 1410^2 .

It is a cyclic number.

It is not a de Polignac number, because 281981389 - 2⁹ = 281980877 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (281981383) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 140990694 + 140990695.

It is an arithmetic number, because the mean of its divisors is an integer number (140990695).

Almost surely, 2^281981389 is an apocalyptic number.

It is an amenable number.

281981389 is a deficient number, since it is larger than the sum of its proper divisors (1).

281981389 is an equidigital number, since it uses as much as digits as its factorization.

281981389 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 248832, while the sum is 49.

The square root of 281981389 is about 16792.3014801426. The cubic root of 281981389 is about 655.7527921959.

The spelling of 281981389 in words is "two hundred eighty-one million, nine hundred eighty-one thousand, three hundred eighty-nine".