21854321 has 4 divisors (see below), whose sum is σ = 21865200. Its totient is φ = 21843444.

The previous prime is 21854317. The next prime is 21854341. The reversal of 21854321 is 12345812.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21854321 - 2² = 21854317 is a prime.

It is a super-2 number, since 2×21854321² = 955222692742082, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21854311) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1451 + ... + 6768.

It is an arithmetic number, because the mean of its divisors is an integer number (5466300).

Almost surely, 2^21854321 is an apocalyptic number.

It is an amenable number.

21854321 is a deficient number, since it is larger than the sum of its proper divisors (10879).

21854321 is an equidigital number, since it uses as much as digits as its factorization.

21854321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10878.

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

The square root of 21854321 is about 4674.8605326790. The cubic root of 21854321 is about 279.5840806175.

The spelling of 21854321 in words is "twenty-one million, eight hundred fifty-four thousand, three hundred twenty-one".