21388325 has 12 divisors (see below), whose sum is σ = 30310560. Its totient is φ = 14666160.

The previous prime is 21388313. The next prime is 21388327. The reversal of 21388325 is 52388312.

It is not a de Polignac number, because 21388325 - 2¹² = 21384229 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21388291 and 21388300.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21388327) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 60935 + ... + 61284.

It is an arithmetic number, because the mean of its divisors is an integer number (2525880).

Almost surely, 2^21388325 is an apocalyptic number.

21388325 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21388325 is a deficient number, since it is larger than the sum of its proper divisors (8922235).

21388325 is a wasteful number, since it uses less digits than its factorization.

21388325 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 122236 (or 122231 counting only the distinct ones).

The product of its digits is 11520, while the sum is 32.

The square root of 21388325 is about 4624.7513446671. The cubic root of 21388325 is about 277.5826120946.

The spelling of 21388325 in words is "twenty-one million, three hundred eighty-eight thousand, three hundred twenty-five".