281555993 has 2 divisors, whose sum is σ = 281555994. Its totient is φ = 281555992.

The previous prime is 281555957. The next prime is 281555999. The reversal of 281555993 is 399555182.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 249892864 + 31663129 = 15808^2 + 5627^2 .

It is a cyclic number.

It is not a de Polignac number, because 281555993 - 2¹⁶ = 281490457 is a prime.

It is not a weakly prime, because it can be changed into another prime (281555999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 140777996 + 140777997.

It is an arithmetic number, because the mean of its divisors is an integer number (140777997).

Almost surely, 2^281555993 is an apocalyptic number.

It is an amenable number.

281555993 is a deficient number, since it is larger than the sum of its proper divisors (1).

281555993 is an equidigital number, since it uses as much as digits as its factorization.

281555993 is an evil number, because the sum of its binary digits is even.

The product of its digits is 486000, while the sum is 47.

The square root of 281555993 is about 16779.6302998606. The cubic root of 281555993 is about 655.4228708844.

The spelling of 281555993 in words is "two hundred eighty-one million, five hundred fifty-five thousand, nine hundred ninety-three".