21021123211 has 20 divisors (see below), whose sum is σ = 23162211000. Its totient is φ = 19077808640.

The previous prime is 21021123199. The next prime is 21021123239. The reversal of 21021123211 is 11232112012.

It is not a de Polignac number, because 21021123211 - 2²⁵ = 20987568779 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21021123311) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 14918475 + ... + 14919883.

It is an arithmetic number, because the mean of its divisors is an integer number (1158110550).

Almost surely, 2^21021123211 is an apocalyptic number.

21021123211 is a deficient number, since it is larger than the sum of its proper divisors (2141087789).

21021123211 is an equidigital number, since it uses as much as digits as its factorization.

21021123211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2472 (or 2439 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 16.

Adding to 21021123211 its reverse (11232112012), we get a palindrome (32253235223).

The spelling of 21021123211 in words is "twenty-one billion, twenty-one million, one hundred twenty-three thousand, two hundred eleven".