213131309 has 2 divisors, whose sum is σ = 213131310. Its totient is φ = 213131308.

The previous prime is 213131299. The next prime is 213131327. The reversal of 213131309 is 903131312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 190302025 + 22829284 = 13795^2 + 4778^2 .

It is a cyclic number.

It is not a de Polignac number, because 213131309 - 2¹⁶ = 213065773 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (213131209) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106565654 + 106565655.

It is an arithmetic number, because the mean of its divisors is an integer number (106565655).

Almost surely, 2^213131309 is an apocalyptic number.

It is an amenable number.

213131309 is a deficient number, since it is larger than the sum of its proper divisors (1).

213131309 is an equidigital number, since it uses as much as digits as its factorization.

213131309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 486, while the sum is 23.

The square root of 213131309 is about 14599.0173984416. The cubic root of 213131309 is about 597.3319581361.

It can be divided in two parts, 21313 and 1309, that added together give a palindrome (22622).

The spelling of 213131309 in words is "two hundred thirteen million, one hundred thirty-one thousand, three hundred nine".