281971993 has 2 divisors, whose sum is σ = 281971994. Its totient is φ = 281971992.

The previous prime is 281971967. The next prime is 281972003. The reversal of 281971993 is 399179182.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 281971264 + 729 = 16792^2 + 27^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-281971993 is a prime.

It is not a weakly prime, because it can be changed into another prime (281971903) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 140985996 + 140985997.

It is an arithmetic number, because the mean of its divisors is an integer number (140985997).

Almost surely, 2^281971993 is an apocalyptic number.

It is an amenable number.

281971993 is a deficient number, since it is larger than the sum of its proper divisors (1).

281971993 is an equidigital number, since it uses as much as digits as its factorization.

281971993 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 244944, while the sum is 49.

The square root of 281971993 is about 16792.0217067511. The cubic root of 281971993 is about 655.7455085927.

The spelling of 281971993 in words is "two hundred eighty-one million, nine hundred seventy-one thousand, nine hundred ninety-three".