213785730121 has 2 divisors, whose sum is σ = 213785730122. Its totient is φ = 213785730120.

The previous prime is 213785730073. The next prime is 213785730149. The reversal of 213785730121 is 121037587312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 201390025225 + 12395704896 = 448765^2 + 111336^2 .

It is a cyclic number.

It is not a de Polignac number, because 213785730121 - 2⁹ = 213785729609 is a prime.

It is not a weakly prime, because it can be changed into another prime (213785530121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106892865060 + 106892865061.

It is an arithmetic number, because the mean of its divisors is an integer number (106892865061).

Almost surely, 2^213785730121 is an apocalyptic number.

It is an amenable number.

213785730121 is a deficient number, since it is larger than the sum of its proper divisors (1).

213785730121 is an equidigital number, since it uses as much as digits as its factorization.

213785730121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 70560, while the sum is 40.

The spelling of 213785730121 in words is "two hundred thirteen billion, seven hundred eighty-five million, seven hundred thirty thousand, one hundred twenty-one".