213957509 has 2 divisors, whose sum is σ = 213957510. Its totient is φ = 213957508.

The previous prime is 213957503. The next prime is 213957511. The reversal of 213957509 is 905759312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 157377025 + 56580484 = 12545^2 + 7522^2 .

It is a cyclic number.

It is not a de Polignac number, because 213957509 - 2⁴ = 213957493 is a prime.

Together with 213957511, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (213957503) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106978754 + 106978755.

It is an arithmetic number, because the mean of its divisors is an integer number (106978755).

Almost surely, 2^213957509 is an apocalyptic number.

It is an amenable number.

213957509 is a deficient number, since it is larger than the sum of its proper divisors (1).

213957509 is an equidigital number, since it uses as much as digits as its factorization.

213957509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 85050, while the sum is 41.

The square root of 213957509 is about 14627.2864537480. The cubic root of 213957509 is about 598.1028120824.

The spelling of 213957509 in words is "two hundred thirteen million, nine hundred fifty-seven thousand, five hundred nine".