21601125 has 96 divisors (see below), whose sum is σ = 48152832. Its totient is φ = 9072000.

The previous prime is 21601121. The next prime is 21601171. The reversal of 21601125 is 52110612.

It is not a de Polignac number, because 21601125 - 2² = 21601121 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21601098 and 21601107.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21601121) 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 95 ways as a sum of consecutive naturals, for example, 102270 + ... + 102480.

It is an arithmetic number, because the mean of its divisors is an integer number (501592).

Almost surely, 2^21601125 is an apocalyptic number.

21601125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21601125 is an abundant number, since it is smaller than the sum of its proper divisors (26551707).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21601125 is a wasteful number, since it uses less digits than its factorization.

21601125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 252 (or 239 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 18.

The square root of 21601125 is about 4647.7010446026. The cubic root of 21601125 is about 278.5001649212.

Adding to 21601125 its reverse (52110612), we get a palindrome (73711737).

The spelling of 21601125 in words is "twenty-one million, six hundred one thousand, one hundred twenty-five".