213857681537 has 2 divisors, whose sum is σ = 213857681538. Its totient is φ = 213857681536.

The previous prime is 213857681509. The next prime is 213857681549. The reversal of 213857681537 is 735186758312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 121054589041 + 92803092496 = 347929^2 + 304636^2 .

It is a cyclic number.

It is not a de Polignac number, because 213857681537 - 2⁸ = 213857681281 is a prime.

It is not a weakly prime, because it can be changed into another prime (213857681237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106928840768 + 106928840769.

It is an arithmetic number, because the mean of its divisors is an integer number (106928840769).

Almost surely, 2^213857681537 is an apocalyptic number.

It is an amenable number.

213857681537 is a deficient number, since it is larger than the sum of its proper divisors (1).

213857681537 is an equidigital number, since it uses as much as digits as its factorization.

213857681537 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8467200, while the sum is 56.

The spelling of 213857681537 in words is "two hundred thirteen billion, eight hundred fifty-seven million, six hundred eighty-one thousand, five hundred thirty-seven".