21021112123 has 16 divisors (see below), whose sum is σ = 23172728832. Its totient is φ = 18909820000.

The previous prime is 21021112111. The next prime is 21021112163. The reversal of 21021112123 is 32121112012.

It is a cyclic number.

It is not a de Polignac number, because 21021112123 - 2⁹ = 21021111611 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21021112097 and 21021112106.

It is not an unprimeable number, because it can be changed into a prime (21021112163) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2340840 + ... + 2349802.

It is an arithmetic number, because the mean of its divisors is an integer number (1448295552).

Almost surely, 2^21021112123 is an apocalyptic number.

21021112123 is a deficient number, since it is larger than the sum of its proper divisors (2151616709).

21021112123 is a wasteful number, since it uses less digits than its factorization.

21021112123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11186.

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

Adding to 21021112123 its reverse (32121112012), we get a palindrome (53142224135).

The spelling of 21021112123 in words is "twenty-one billion, twenty-one million, one hundred twelve thousand, one hundred twenty-three".