213857681549 has 2 divisors, whose sum is σ = 213857681550. Its totient is φ = 213857681548.

The previous prime is 213857681537. The next prime is 213857681551. The reversal of 213857681549 is 945186758312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 179022072100 + 34835609449 = 423110^2 + 186643^2 .

It is a cyclic number.

It is not a de Polignac number, because 213857681549 - 2⁸ = 213857681293 is a prime.

Together with 213857681551, 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 (213857681509) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106928840774 + 106928840775.

It is an arithmetic number, because the mean of its divisors is an integer number (106928840775).

Almost surely, 2^213857681549 is an apocalyptic number.

It is an amenable number.

213857681549 is a deficient number, since it is larger than the sum of its proper divisors (1).

213857681549 is an equidigital number, since it uses as much as digits as its factorization.

213857681549 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 14515200, while the sum is 59.

The spelling of 213857681549 in words is "two hundred thirteen billion, eight hundred fifty-seven million, six hundred eighty-one thousand, five hundred forty-nine".