659684981 has 2 divisors, whose sum is σ = 659684982. Its totient is φ = 659684980.

The previous prime is 659684969. The next prime is 659685029. The reversal of 659684981 is 189486956.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 361570225 + 298114756 = 19015^2 + 17266^2 .

It is a cyclic number.

It is not a de Polignac number, because 659684981 - 2⁶ = 659684917 is a prime.

It is a super-2 number, since 2×659684981² = 870368548313940722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (659684281) 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, 329842490 + 329842491.

It is an arithmetic number, because the mean of its divisors is an integer number (329842491).

Almost surely, 2^659684981 is an apocalyptic number.

It is an amenable number.

659684981 is a deficient number, since it is larger than the sum of its proper divisors (1).

659684981 is an equidigital number, since it uses as much as digits as its factorization.

659684981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3732480, while the sum is 56.

The square root of 659684981 is about 25684.3333765936. Note that the first 4 decimals coincide. The cubic root of 659684981 is about 870.5202248227.

The spelling of 659684981 in words is "six hundred fifty-nine million, six hundred eighty-four thousand, nine hundred eighty-one".