258399781 has 2 divisors, whose sum is σ = 258399782. Its totient is φ = 258399780.

The previous prime is 258399767. The next prime is 258399809. The reversal of 258399781 is 187993852.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 159794881 + 98604900 = 12641^2 + 9930^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-258399781 is a prime.

It is a super-2 number, since 2×258399781² = 133540893641695922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (258399761) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 129199890 + 129199891.

It is an arithmetic number, because the mean of its divisors is an integer number (129199891).

Almost surely, 2^258399781 is an apocalyptic number.

It is an amenable number.

258399781 is a deficient number, since it is larger than the sum of its proper divisors (1).

258399781 is an equidigital number, since it uses as much as digits as its factorization.

258399781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1088640, while the sum is 52.

The square root of 258399781 is about 16074.8182260329. The cubic root of 258399781 is about 636.9383234721.

The spelling of 258399781 in words is "two hundred fifty-eight million, three hundred ninety-nine thousand, seven hundred eighty-one".