21109061 has 2 divisors, whose sum is σ = 21109062. Its totient is φ = 21109060.

The previous prime is 21109007. The next prime is 21109069. The reversal of 21109061 is 16090112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21104836 + 4225 = 4594^2 + 65^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21109061 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21109069) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10554530 + 10554531.

It is an arithmetic number, because the mean of its divisors is an integer number (10554531).

Almost surely, 2^21109061 is an apocalyptic number.

It is an amenable number.

21109061 is a deficient number, since it is larger than the sum of its proper divisors (1).

21109061 is an equidigital number, since it uses as much as digits as its factorization.

21109061 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 108, while the sum is 20.

The square root of 21109061 is about 4594.4598159087. The cubic root of 21109061 is about 276.3691980297.

Adding to 21109061 its reverse (16090112), we get a palindrome (37199173).

It can be divided in two parts, 2 and 1109061, that multiplied together give a palindrome (2218122).

The spelling of 21109061 in words is "twenty-one million, one hundred nine thousand, sixty-one".