21551325 has 24 divisors (see below), whose sum is σ = 37729728. Its totient is φ = 10817280.

The previous prime is 21551323. The next prime is 21551351. The reversal of 21551325 is 52315512.

It is a happy number.

It is not a de Polignac number, because 21551325 - 2¹ = 21551323 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21551295 and 21551304.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21551323) 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 23 ways as a sum of consecutive naturals, for example, 7177 + ... + 9726.

It is an arithmetic number, because the mean of its divisors is an integer number (1572072).

Almost surely, 2^21551325 is an apocalyptic number.

21551325 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21551325 is a deficient number, since it is larger than the sum of its proper divisors (16178403).

21551325 is a wasteful number, since it uses less digits than its factorization.

21551325 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16933 (or 16928 counting only the distinct ones).

The product of its digits is 1500, while the sum is 24.

The square root of 21551325 is about 4642.3404657565. The cubic root of 21551325 is about 278.2859788522.

Adding to 21551325 its reverse (52315512), we get a palindrome (73866837).

The spelling of 21551325 in words is "twenty-one million, five hundred fifty-one thousand, three hundred twenty-five".