21911611 has 2 divisors, whose sum is σ = 21911612. Its totient is φ = 21911610.

The previous prime is 21911599. The next prime is 21911633. The reversal of 21911611 is 11611912.

It is an a-pointer prime, because the next prime (21911633) can be obtained adding 21911611 to its sum of digits (22).

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21911611 is a prime.

It is not a weakly prime, because it can be changed into another prime (21911641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10955805 + 10955806.

It is an arithmetic number, because the mean of its divisors is an integer number (10955806).

Almost surely, 2^21911611 is an apocalyptic number.

21911611 is a deficient number, since it is larger than the sum of its proper divisors (1).

21911611 is an equidigital number, since it uses as much as digits as its factorization.

21911611 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 108, while the sum is 22.

The square root of 21911611 is about 4680.9839777551. The cubic root of 21911611 is about 279.8281726376.

It can be divided in two parts, 21911 and 611, that added together give a palindrome (22522).

The spelling of 21911611 in words is "twenty-one million, nine hundred eleven thousand, six hundred eleven".