21221210011 has 4 divisors (see below), whose sum is σ = 21511911592. Its totient is φ = 20930508432.

The previous prime is 21221209957. The next prime is 21221210033. The reversal of 21221210011 is 11001212212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21221210011 - 2⁷ = 21221209883 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21221209973 and 21221210000.

It is not an unprimeable number, because it can be changed into a prime (21221210111) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 145350681 + ... + 145350826.

It is an arithmetic number, because the mean of its divisors is an integer number (5377977898).

Almost surely, 2^21221210011 is an apocalyptic number.

21221210011 is a deficient number, since it is larger than the sum of its proper divisors (290701581).

21221210011 is an equidigital number, since it uses as much as digits as its factorization.

21221210011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 290701580.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 21221210011 its reverse (11001212212), we get a palindrome (32222422223).

The spelling of 21221210011 in words is "twenty-one billion, two hundred twenty-one million, two hundred ten thousand, eleven".