21253841 has 8 divisors (see below), whose sum is σ = 24366144. Its totient is φ = 18160560.

The previous prime is 21253763. The next prime is 21253849. The reversal of 21253841 is 14835212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21253841 is a prime.

It is a Duffinian number.

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 21253841.

It is not an unprimeable number, because it can be changed into a prime (21253849) 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 7 ways as a sum of consecutive naturals, for example, 2270 + ... + 6903.

It is an arithmetic number, because the mean of its divisors is an integer number (3045768).

Almost surely, 2^21253841 is an apocalyptic number.

It is an amenable number.

21253841 is a deficient number, since it is larger than the sum of its proper divisors (3112303).

21253841 is an equidigital number, since it uses as much as digits as its factorization.

21253841 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9511.

The product of its digits is 1920, while the sum is 26.

The square root of 21253841 is about 4610.1888247663. The cubic root of 21253841 is about 276.9996003244. Note that the first 3 decimals are identical.

The spelling of 21253841 in words is "twenty-one million, two hundred fifty-three thousand, eight hundred forty-one".