21206011 has 2 divisors, whose sum is σ = 21206012. Its totient is φ = 21206010.

The previous prime is 21205999. The next prime is 21206117. The reversal of 21206011 is 11060212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21206011 - 2¹⁷ = 21074939 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21205982 and 21206000.

It is not a weakly prime, because it can be changed into another prime (21203011) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10603005 + 10603006.

It is an arithmetic number, because the mean of its divisors is an integer number (10603006).

Almost surely, 2^21206011 is an apocalyptic number.

21206011 is a deficient number, since it is larger than the sum of its proper divisors (1).

21206011 is an equidigital number, since it uses as much as digits as its factorization.

21206011 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24, while the sum is 13.

The square root of 21206011 is about 4604.9984799129. The cubic root of 21206011 is about 276.7916560782.

Adding to 21206011 its reverse (11060212), we get a palindrome (32266223).

The spelling of 21206011 in words is "twenty-one million, two hundred six thousand, eleven".