259520021 has 2 divisors, whose sum is σ = 259520022. Its totient is φ = 259520020.

The previous prime is 259519991. The next prime is 259520029. The reversal of 259520021 is 120025952.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 259371025 + 148996 = 16105^2 + 386^2 .

It is a cyclic number.

It is not a de Polignac number, because 259520021 - 2⁶ = 259519957 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (259520029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 129760010 + 129760011.

It is an arithmetic number, because the mean of its divisors is an integer number (129760011).

Almost surely, 2^259520021 is an apocalyptic number.

It is an amenable number.

259520021 is a deficient number, since it is larger than the sum of its proper divisors (1).

259520021 is an equidigital number, since it uses as much as digits as its factorization.

259520021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1800, while the sum is 26.

The square root of 259520021 is about 16109.6251042661. The cubic root of 259520021 is about 637.8574356430.

Adding to 259520021 its reverse (120025952), we get a palindrome (379545973).

The spelling of 259520021 in words is "two hundred fifty-nine million, five hundred twenty thousand, twenty-one".