258696721 has 2 divisors, whose sum is σ = 258696722. Its totient is φ = 258696720.

The previous prime is 258696679. The next prime is 258696731. The reversal of 258696721 is 127696852.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 258566400 + 130321 = 16080^2 + 361^2 .

It is a cyclic number.

It is not a de Polignac number, because 258696721 - 2¹⁵ = 258663953 is a prime.

It is not a weakly prime, because it can be changed into another prime (258696731) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 129348360 + 129348361.

It is an arithmetic number, because the mean of its divisors is an integer number (129348361).

Almost surely, 2^258696721 is an apocalyptic number.

It is an amenable number.

258696721 is a deficient number, since it is larger than the sum of its proper divisors (1).

258696721 is an equidigital number, since it uses as much as digits as its factorization.

258696721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 362880, while the sum is 46.

The square root of 258696721 is about 16084.0517594293. The cubic root of 258696721 is about 637.1822092113.

The spelling of 258696721 in words is "two hundred fifty-eight million, six hundred ninety-six thousand, seven hundred twenty-one".