281912381 has 2 divisors, whose sum is σ = 281912382. Its totient is φ = 281912380.

The previous prime is 281912347. The next prime is 281912383. The reversal of 281912381 is 183219182.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 281904100 + 8281 = 16790^2 + 91^2 .

It is a cyclic number.

It is not a de Polignac number, because 281912381 - 2⁶ = 281912317 is a prime.

It is a super-2 number, since 2×281912381² = 158949181122178322, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 281912383, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (281912383) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 140956190 + 140956191.

It is an arithmetic number, because the mean of its divisors is an integer number (140956191).

Almost surely, 2^281912381 is an apocalyptic number.

It is an amenable number.

281912381 is a deficient number, since it is larger than the sum of its proper divisors (1).

281912381 is an equidigital number, since it uses as much as digits as its factorization.

281912381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6912, while the sum is 35.

The square root of 281912381 is about 16790.2466033111. The cubic root of 281912381 is about 655.6992947165.

The spelling of 281912381 in words is "two hundred eighty-one million, nine hundred twelve thousand, three hundred eighty-one".