201121021609 has 2 divisors, whose sum is σ = 201121021610. Its totient is φ = 201121021608.

The previous prime is 201121021603. The next prime is 201121021649. The reversal of 201121021609 is 906120121102.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 186054195600 + 15066826009 = 431340^2 + 122747^2 .

It is a cyclic number.

It is not a de Polignac number, because 201121021609 - 2³ = 201121021601 is a prime.

It is not a weakly prime, because it can be changed into another prime (201121021601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100560510804 + 100560510805.

It is an arithmetic number, because the mean of its divisors is an integer number (100560510805).

Almost surely, 2^201121021609 is an apocalyptic number.

It is an amenable number.

201121021609 is a deficient number, since it is larger than the sum of its proper divisors (1).

201121021609 is an equidigital number, since it uses as much as digits as its factorization.

201121021609 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 432, while the sum is 25.

The spelling of 201121021609 in words is "two hundred one billion, one hundred twenty-one million, twenty-one thousand, six hundred nine".