21440625 has 24 divisors (see below), whose sum is σ = 35747712. Its totient is φ = 11430000.

The previous prime is 21440609. The next prime is 21440647. The reversal of 21440625 is 52604412.

It is not a de Polignac number, because 21440625 - 2⁴ = 21440609 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21440595 and 21440604.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 8232 + ... + 10518.

It is an arithmetic number, because the mean of its divisors is an integer number (1489488).

Almost surely, 2^21440625 is an apocalyptic number.

21440625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21440625 is a deficient number, since it is larger than the sum of its proper divisors (14307087).

21440625 is an frugal number, since it uses more digits than its factorization.

21440625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2315 (or 2295 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 24.

The square root of 21440625 is about 4630.4022503450. The cubic root of 21440625 is about 277.8086817469.

The spelling of 21440625 in words is "twenty-one million, four hundred forty thousand, six hundred twenty-five".