21043625 has 16 divisors (see below), whose sum is σ = 26607360. Its totient is φ = 16614000.

The previous prime is 21043613. The next prime is 21043661. The reversal of 21043625 is 52634012.

It is not a de Polignac number, because 21043625 - 2⁴ = 21043609 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21043625.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8810 + ... + 10940.

It is an arithmetic number, because the mean of its divisors is an integer number (1662960).

Almost surely, 2^21043625 is an apocalyptic number.

21043625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21043625 is a deficient number, since it is larger than the sum of its proper divisors (5563735).

21043625 is an equidigital number, since it uses as much as digits as its factorization.

21043625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2225 (or 2215 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 21043625 is about 4587.3331032311. Note that the first 3 decimals coincide. The cubic root of 21043625 is about 276.0833300509.

Adding to 21043625 its reverse (52634012), we get a palindrome (73677637).

The spelling of 21043625 in words is "twenty-one million, forty-three thousand, six hundred twenty-five".