281299981 has 2 divisors, whose sum is σ = 281299982. Its totient is φ = 281299980.

The previous prime is 281299979. The next prime is 281299987. The reversal of 281299981 is 189992182.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 281232900 + 67081 = 16770^2 + 259^2 .

It is a cyclic number.

It is not a de Polignac number, because 281299981 - 2¹ = 281299979 is a prime.

It is a super-2 number, since 2×281299981² = 158259358621200722, which contains 22 as substring.

Together with 281299979, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (281299987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 140649990 + 140649991.

It is an arithmetic number, because the mean of its divisors is an integer number (140649991).

Almost surely, 2^281299981 is an apocalyptic number.

It is an amenable number.

281299981 is a deficient number, since it is larger than the sum of its proper divisors (1).

281299981 is an equidigital number, since it uses as much as digits as its factorization.

281299981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 186624, while the sum is 49.

The square root of 281299981 is about 16771.9999105652. Note that the first 4 decimals coincide. The cubic root of 281299981 is about 655.2241572980.

The spelling of 281299981 in words is "two hundred eighty-one million, two hundred ninety-nine thousand, nine hundred eighty-one".