21010112123 has 32 divisors (see below), whose sum is σ = 28549366272. Its totient is φ = 14930035200.

The previous prime is 21010112089. The next prime is 21010112159. The reversal of 21010112123 is 32121101012.

It is a cyclic number.

It is not a de Polignac number, because 21010112123 - 2¹⁸ = 21009849979 is a prime.

It is a super-2 number, since 2×21010112123² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21010112098 and 21010112107.

It is not an unprimeable number, because it can be changed into a prime (21010112023) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 43358 + ... + 209523.

It is an arithmetic number, because the mean of its divisors is an integer number (892167696).

Almost surely, 2^21010112123 is an apocalyptic number.

21010112123 is a deficient number, since it is larger than the sum of its proper divisors (7539254149).

21010112123 is a wasteful number, since it uses less digits than its factorization.

21010112123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 252995.

The product of its (nonzero) digits is 24, while the sum is 14.

Adding to 21010112123 its reverse (32121101012), we get a palindrome (53131213135).

The spelling of 21010112123 in words is "twenty-one billion, ten million, one hundred twelve thousand, one hundred twenty-three".