209124521 has 2 divisors, whose sum is σ = 209124522. Its totient is φ = 209124520.

The previous prime is 209124493. The next prime is 209124529. The reversal of 209124521 is 125421902.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 196308121 + 12816400 = 14011^2 + 3580^2 .

It is a cyclic number.

It is not a de Polignac number, because 209124521 - 2¹⁸ = 208862377 is a prime.

It is not a weakly prime, because it can be changed into another prime (209124529) 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, 104562260 + 104562261.

It is an arithmetic number, because the mean of its divisors is an integer number (104562261).

Almost surely, 2^209124521 is an apocalyptic number.

It is an amenable number.

209124521 is a deficient number, since it is larger than the sum of its proper divisors (1).

209124521 is an equidigital number, since it uses as much as digits as its factorization.

209124521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1440, while the sum is 26.

The square root of 209124521 is about 14461.1383023606. The cubic root of 209124521 is about 593.5650481224.

The spelling of 209124521 in words is "two hundred nine million, one hundred twenty-four thousand, five hundred twenty-one".