21441021 has 8 divisors (see below), whose sum is σ = 32672064. Its totient is φ = 12252000.

The previous prime is 21441011. The next prime is 21441031. The reversal of 21441021 is 12014412.

It is an interprime number because it is at equal distance from previous prime (21441011) and next prime (21441031).

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

It is not a de Polignac number, because 21441021 - 2⁵ = 21440989 is a prime.

It is a Smith number, since the sum of its digits (15) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21441001) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 510480 + ... + 510521.

It is an arithmetic number, because the mean of its divisors is an integer number (4084008).

Almost surely, 2^21441021 is an apocalyptic number.

21441021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21441021 is a deficient number, since it is larger than the sum of its proper divisors (11231043).

21441021 is a wasteful number, since it uses less digits than its factorization.

21441021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1021011.

The product of its (nonzero) digits is 64, while the sum is 15.

The square root of 21441021 is about 4630.4450110114. The cubic root of 21441021 is about 277.8103920757.

Adding to 21441021 its reverse (12014412), we get a palindrome (33455433).

The spelling of 21441021 in words is "twenty-one million, four hundred forty-one thousand, twenty-one".