21123112 has 16 divisors (see below), whose sum is σ = 41935860. Its totient is φ = 9940224.

The previous prime is 21123103. The next prime is 21123119. The reversal of 21123112 is 21132112.

It can be written as a sum of positive squares in 2 ways, for example, as 15952036 + 5171076 = 3994^2 + 2274^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21123092 and 21123101.

It is not an unprimeable number, because it can be changed into a prime (21123119) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 77523 + ... + 77794.

Almost surely, 2^21123112 is an apocalyptic number.

It is an amenable number.

21123112 is a deficient number, since it is larger than the sum of its proper divisors (20812748).

21123112 is a wasteful number, since it uses less digits than its factorization.

21123112 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155340 (or 155336 counting only the distinct ones).

The product of its digits is 24, while the sum is 13.

The square root of 21123112 is about 4595.9886857998. The cubic root of 21123112 is about 276.4305050722.

Adding to 21123112 its reverse (21132112), we get a palindrome (42255224).

The spelling of 21123112 in words is "twenty-one million, one hundred twenty-three thousand, one hundred twelve".