201820609 has 2 divisors, whose sum is σ = 201820610. Its totient is φ = 201820608.

The previous prime is 201820547. The next prime is 201820631. The reversal of 201820609 is 906028102.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 111513600 + 90307009 = 10560^2 + 9503^2 .

It is a cyclic number.

It is not a de Polignac number, because 201820609 - 2⁹ = 201820097 is a prime.

It is not a weakly prime, because it can be changed into another prime (201820709) 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, 100910304 + 100910305.

It is an arithmetic number, because the mean of its divisors is an integer number (100910305).

Almost surely, 2^201820609 is an apocalyptic number.

It is an amenable number.

201820609 is a deficient number, since it is larger than the sum of its proper divisors (1).

201820609 is an equidigital number, since it uses as much as digits as its factorization.

201820609 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 201820609 is about 14206.3580484232. The cubic root of 201820609 is about 586.5726879349.

The spelling of 201820609 in words is "two hundred one million, eight hundred twenty thousand, six hundred nine".