21003125 has 48 divisors (see below), whose sum is σ = 31497984. Its totient is φ = 13800000.

The previous prime is 21003121. The next prime is 21003139. The reversal of 21003125 is 52130012.

It is a happy number.

It is not a de Polignac number, because 21003125 - 2² = 21003121 is a prime.

It is a super-2 number, since 2×21003125² = 882262519531250, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21003121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 446852 + ... + 446898.

It is an arithmetic number, because the mean of its divisors is an integer number (656208).

Almost surely, 2^21003125 is an apocalyptic number.

21003125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21003125 is a deficient number, since it is larger than the sum of its proper divisors (10494859).

21003125 is an equidigital number, since it uses as much as digits as its factorization.

21003125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96 (or 76 counting only the distinct ones).

The product of its (nonzero) digits is 60, while the sum is 14.

The square root of 21003125 is about 4582.9166477256. The cubic root of 21003125 is about 275.9061020991.

Adding to 21003125 its reverse (52130012), we get a palindrome (73133137).

It can be divided in two parts, 2100 and 3125, that added together give a palindrome (5225).

The spelling of 21003125 in words is "twenty-one million, three thousand, one hundred twenty-five".