21112125 has 16 divisors (see below), whose sum is σ = 35131200. Its totient is φ = 11259600.

The previous prime is 21112121. The next prime is 21112127. The reversal of 21112125 is 52121112.

It is not a de Polignac number, because 21112125 - 2² = 21112121 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21112121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27775 + ... + 28524.

It is an arithmetic number, because the mean of its divisors is an integer number (2195700).

Almost surely, 2^21112125 is an apocalyptic number.

21112125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21112125 is a deficient number, since it is larger than the sum of its proper divisors (14019075).

21112125 is an equidigital number, since it uses as much as digits as its factorization.

21112125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56317 (or 56307 counting only the distinct ones).

The product of its digits is 40, while the sum is 15.

The square root of 21112125 is about 4594.7932488851. The cubic root of 21112125 is about 276.3825691322.

Adding to 21112125 its reverse (52121112), we get a palindrome (73233237).

The spelling of 21112125 in words is "twenty-one million, one hundred twelve thousand, one hundred twenty-five".