21126125 has 8 divisors (see below), whose sum is σ = 26365560. Its totient is φ = 16900800.

The previous prime is 21126109. The next prime is 21126169. The reversal of 21126125 is 52162112.

It can be written as a sum of positive squares in 4 ways, for example, as 1394761 + 19731364 = 1181^2 + 4442^2 .

It is not a de Polignac number, because 21126125 - 2⁴ = 21126109 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21126097 and 21126106.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 84380 + ... + 84629.

It is an arithmetic number, because the mean of its divisors is an integer number (3295695).

Almost surely, 2^21126125 is an apocalyptic number.

21126125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21126125 is a deficient number, since it is larger than the sum of its proper divisors (5239435).

21126125 is an equidigital number, since it uses as much as digits as its factorization.

21126125 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 169024 (or 169014 counting only the distinct ones).

The product of its digits is 240, while the sum is 20.

The square root of 21126125 is about 4596.3164599492. The cubic root of 21126125 is about 276.4436477934.

Adding to 21126125 its reverse (52162112), we get a palindrome (73288237).

The spelling of 21126125 in words is "twenty-one million, one hundred twenty-six thousand, one hundred twenty-five".