21611011 has 2 divisors, whose sum is σ = 21611012. Its totient is φ = 21611010.

The previous prime is 21610991. The next prime is 21611017. The reversal of 21611011 is 11011612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21611011 - 2⁹ = 21610499 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21610982 and 21611000.

It is not a weakly prime, because it can be changed into another prime (21611017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10805505 + 10805506.

It is an arithmetic number, because the mean of its divisors is an integer number (10805506).

Almost surely, 2^21611011 is an apocalyptic number.

21611011 is a deficient number, since it is larger than the sum of its proper divisors (1).

21611011 is an equidigital number, since it uses as much as digits as its factorization.

21611011 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12, while the sum is 13.

The square root of 21611011 is about 4648.7644595096. The cubic root of 21611011 is about 278.5426446951.

Adding to 21611011 its reverse (11011612), we get a palindrome (32622623).

The spelling of 21611011 in words is "twenty-one million, six hundred eleven thousand, eleven".