21012222211 has 4 divisors (see below), whose sum is σ = 21019297624. Its totient is φ = 21005146800.

The previous prime is 21012222193. The next prime is 21012222221. The reversal of 21012222211 is 11222221012.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21012222211 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21012222221) 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, 3533250 + ... + 3539191.

It is an arithmetic number, because the mean of its divisors is an integer number (5254824406).

Almost surely, 2^21012222211 is an apocalyptic number.

21012222211 is a deficient number, since it is larger than the sum of its proper divisors (7075413).

21012222211 is an equidigital number, since it uses as much as digits as its factorization.

21012222211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7075412.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21012222211 its reverse (11222221012), we get a palindrome (32234443223).

The spelling of 21012222211 in words is "twenty-one billion, twelve million, two hundred twenty-two thousand, two hundred eleven".