281881021 has 2 divisors, whose sum is σ = 281881022. Its totient is φ = 281881020.

The previous prime is 281881013. The next prime is 281881049. The reversal of 281881021 is 120188182.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 202920025 + 78960996 = 14245^2 + 8886^2 .

It is a cyclic number.

It is not a de Polignac number, because 281881021 - 2³ = 281881013 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 (281888021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 140940510 + 140940511.

It is an arithmetic number, because the mean of its divisors is an integer number (140940511).

Almost surely, 2^281881021 is an apocalyptic number.

It is an amenable number.

281881021 is a deficient number, since it is larger than the sum of its proper divisors (1).

281881021 is an equidigital number, since it uses as much as digits as its factorization.

281881021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2048, while the sum is 31.

The square root of 281881021 is about 16789.3127018351. The cubic root of 281881021 is about 655.6749804334.

The spelling of 281881021 in words is "two hundred eighty-one million, eight hundred eighty-one thousand, twenty-one".