21396441 has 8 divisors (see below), whose sum is σ = 31122144. Its totient is φ = 12967520.

The previous prime is 21396379. The next prime is 21396449. The reversal of 21396441 is 14469312.

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 21396441 - 2⁹ = 21395929 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21396399 and 21396408.

It is not an unprimeable number, because it can be changed into a prime (21396449) 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, 324156 + ... + 324221.

It is an arithmetic number, because the mean of its divisors is an integer number (3890268).

Almost surely, 2^21396441 is an apocalyptic number.

It is an amenable number.

21396441 is a deficient number, since it is larger than the sum of its proper divisors (9725703).

21396441 is a wasteful number, since it uses less digits than its factorization.

21396441 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 648391.

The product of its digits is 5184, while the sum is 30.

The square root of 21396441 is about 4625.6287140236. The cubic root of 21396441 is about 277.6177180941.

The spelling of 21396441 in words is "twenty-one million, three hundred ninety-six thousand, four hundred forty-one".