21676841 has 4 divisors (see below), whose sum is σ = 22085892. Its totient is φ = 21267792.

The previous prime is 21676829. The next prime is 21676847. The reversal of 21676841 is 14867612.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 19545241 + 2131600 = 4421^2 + 1460^2 .

It is a cyclic number.

It is not a de Polignac number, because 21676841 - 2¹⁸ = 21414697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21676847) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 204446 + ... + 204551.

It is an arithmetic number, because the mean of its divisors is an integer number (5521473).

Almost surely, 2^21676841 is an apocalyptic number.

It is an amenable number.

21676841 is a deficient number, since it is larger than the sum of its proper divisors (409051).

21676841 is an equidigital number, since it uses as much as digits as its factorization.

21676841 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 409050.

The product of its digits is 16128, while the sum is 35.

The square root of 21676841 is about 4655.8394516993. The cubic root of 21676841 is about 278.8251839265.

The spelling of 21676841 in words is "twenty-one million, six hundred seventy-six thousand, eight hundred forty-one".