21321125 has 36 divisors (see below), whose sum is σ = 31486572. Its totient is φ = 14372400.

The previous prime is 21321121. The next prime is 21321133. The reversal of 21321125 is 52112312.

It is a happy number.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It can be written as a sum of positive squares in 2 ways, for example, as 682276 + 20638849 = 826^2 + 4543^2 .

It is not a de Polignac number, because 21321125 - 2² = 21321121 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21321121) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 361346 + ... + 361404.

It is an arithmetic number, because the mean of its divisors is an integer number (874627).

Almost surely, 2^21321125 is an apocalyptic number.

21321125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21321125 is a deficient number, since it is larger than the sum of its proper divisors (10165447).

21321125 is an frugal number, since it uses more digits than its factorization.

21321125 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 147 (or 71 counting only the distinct ones).

The product of its digits is 120, while the sum is 17.

The square root of 21321125 is about 4617.4803735371. The cubic root of 21321125 is about 277.2915947354.

Adding to 21321125 its reverse (52112312), we get a palindrome (73433437).

The spelling of 21321125 in words is "twenty-one million, three hundred twenty-one thousand, one hundred twenty-five".