21984425 has 24 divisors (see below), whose sum is σ = 29640960. Its totient is φ = 16113600.

The previous prime is 21984421. The next prime is 21984449. The reversal of 21984425 is 52448912.

It is not a de Polignac number, because 21984425 - 2² = 21984421 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21984421) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13979 + ... + 15471.

It is an arithmetic number, because the mean of its divisors is an integer number (1235040).

Almost surely, 2^21984425 is an apocalyptic number.

21984425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21984425 is a deficient number, since it is larger than the sum of its proper divisors (7656535).

21984425 is a wasteful number, since it uses less digits than its factorization.

21984425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1553 (or 1548 counting only the distinct ones).

The product of its digits is 23040, while the sum is 35.

The square root of 21984425 is about 4688.7551652864. The cubic root of 21984425 is about 280.1377935725.

The spelling of 21984425 in words is "twenty-one million, nine hundred eighty-four thousand, four hundred twenty-five".