21331125 has 48 divisors (see below), whose sum is σ = 39164736. Its totient is φ = 11167200.

The previous prime is 21331109. The next prime is 21331127. The reversal of 21331125 is 52113312.

It is not a de Polignac number, because 21331125 - 2⁴ = 21331109 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21331098 and 21331107.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21331127) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 75234 + ... + 75516.

It is an arithmetic number, because the mean of its divisors is an integer number (815932).

Almost surely, 2^21331125 is an apocalyptic number.

21331125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21331125 is a deficient number, since it is larger than the sum of its proper divisors (17833611).

21331125 is a wasteful number, since it uses less digits than its factorization.

21331125 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 371 (or 358 counting only the distinct ones).

The product of its digits is 180, while the sum is 18.

The square root of 21331125 is about 4618.5630882343. The cubic root of 21331125 is about 277.3349395799.

Adding to 21331125 its reverse (52113312), we get a palindrome (73444437).

The spelling of 21331125 in words is "twenty-one million, three hundred thirty-one thousand, one hundred twenty-five".