21381043 has 8 divisors (see below), whose sum is σ = 21785600. Its totient is φ = 20979648.

The previous prime is 21381037. The next prime is 21381047. The reversal of 21381043 is 34018312.

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-21381043 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21381047) 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, 16078 + ... + 17356.

It is an arithmetic number, because the mean of its divisors is an integer number (2723200).

Almost surely, 2^21381043 is an apocalyptic number.

21381043 is a deficient number, since it is larger than the sum of its proper divisors (404557).

21381043 is a wasteful number, since it uses less digits than its factorization.

21381043 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1581.

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 21381043 is about 4623.9639920743. The cubic root of 21381043 is about 277.5511060272.

Adding to 21381043 its reverse (34018312), we get a palindrome (55399355).

The spelling of 21381043 in words is "twenty-one million, three hundred eighty-one thousand, forty-three".