21211109 has 2 divisors, whose sum is σ = 21211110. Its totient is φ = 21211108.

The previous prime is 21211079. The next prime is 21211139. The reversal of 21211109 is 90111212.

It is a balanced prime because it is at equal distance from previous prime (21211079) and next prime (21211139).

It can be written as a sum of positive squares in only one way, i.e., 12271009 + 8940100 = 3503^2 + 2990^2 .

It is a cyclic number.

It is not a de Polignac number, because 21211109 - 2²⁴ = 4433893 is a prime.

It is a super-2 number, since 2×21211109² = 899822290019762, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21211139) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605554 + 10605555.

It is an arithmetic number, because the mean of its divisors is an integer number (10605555).

Almost surely, 2^21211109 is an apocalyptic number.

It is an amenable number.

21211109 is a deficient number, since it is larger than the sum of its proper divisors (1).

21211109 is an equidigital number, since it uses as much as digits as its factorization.

21211109 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 17.

The square root of 21211109 is about 4605.5519756051. The cubic root of 21211109 is about 276.8138348652.

The spelling of 21211109 in words is "twenty-one million, two hundred eleven thousand, one hundred nine".