21333641 has 8 divisors (see below), whose sum is σ = 24509184. Its totient is φ = 18190080.

The previous prime is 21333619. The next prime is 21333649. The reversal of 21333641 is 14633312.

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

It is a cyclic number.

It is not a de Polignac number, because 21333641 - 2¹⁸ = 21071497 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21333649) 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, 6545 + ... + 9246.

It is an arithmetic number, because the mean of its divisors is an integer number (3063648).

Almost surely, 2^21333641 is an apocalyptic number.

It is an amenable number.

21333641 is a deficient number, since it is larger than the sum of its proper divisors (3175543).

21333641 is a wasteful number, since it uses less digits than its factorization.

21333641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15991.

The product of its digits is 1296, while the sum is 23.

The square root of 21333641 is about 4618.8354592906. The cubic root of 21333641 is about 277.3458430098.

Adding to 21333641 its reverse (14633312), we get a palindrome (35966953).

The spelling of 21333641 in words is "twenty-one million, three hundred thirty-three thousand, six hundred forty-one".