21201109 has 2 divisors, whose sum is σ = 21201110. Its totient is φ = 21201108.

The previous prime is 21201083. The next prime is 21201121. The reversal of 21201109 is 90110212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14326225 + 6874884 = 3785^2 + 2622^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21201109 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21201092 and 21201101.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21201199) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600554 + 10600555.

It is an arithmetic number, because the mean of its divisors is an integer number (10600555).

Almost surely, 2^21201109 is an apocalyptic number.

It is an amenable number.

21201109 is a deficient number, since it is larger than the sum of its proper divisors (1).

21201109 is an equidigital number, since it uses as much as digits as its factorization.

21201109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 36, while the sum is 16.

The square root of 21201109 is about 4604.4662014179. The cubic root of 21201109 is about 276.7703266344.

The spelling of 21201109 in words is "twenty-one million, two hundred one thousand, one hundred nine".