21668325 has 48 divisors (see below), whose sum is σ = 41366400. Its totient is φ = 9803520.

The previous prime is 21668299. The next prime is 21668327. The reversal of 21668325 is 52386612.

It is not a de Polignac number, because 21668325 - 2⁶ = 21668261 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21668327) 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, 78087 + ... + 78363.

It is an arithmetic number, because the mean of its divisors is an integer number (861800).

Almost surely, 2^21668325 is an apocalyptic number.

21668325 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21668325 is a deficient number, since it is larger than the sum of its proper divisors (19698075).

21668325 is a wasteful number, since it uses less digits than its factorization.

21668325 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 446 (or 441 counting only the distinct ones).

The product of its digits is 17280, while the sum is 33.

The square root of 21668325 is about 4654.9248114228. The cubic root of 21668325 is about 278.7886659013.

The spelling of 21668325 in words is "twenty-one million, six hundred sixty-eight thousand, three hundred twenty-five".