21038125 has 20 divisors (see below), whose sum is σ = 26963244. Its totient is φ = 16400000.

The previous prime is 21038117. The next prime is 21038141. The reversal of 21038125 is 52183012.

It can be written as a sum of positive squares in 10 ways, for example, as 20820969 + 217156 = 4563^2 + 466^2 .

It is not a de Polignac number, because 21038125 - 2³ = 21038117 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21038096 and 21038105.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 25215 + ... + 26035.

Almost surely, 2^21038125 is an apocalyptic number.

21038125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21038125 is a deficient number, since it is larger than the sum of its proper divisors (5925119).

21038125 is an frugal number, since it uses more digits than its factorization.

21038125 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 882 (or 867 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 22.

The square root of 21038125 is about 4586.7335872056. The cubic root of 21038125 is about 276.0592754085.

It can be divided in two parts, 210381 and 25, that multiplied together give a palindrome (5259525).

The spelling of 21038125 in words is "twenty-one million, thirty-eight thousand, one hundred twenty-five".