21844651 has 2 divisors, whose sum is σ = 21844652. Its totient is φ = 21844650.

The previous prime is 21844637. The next prime is 21844679. The reversal of 21844651 is 15644812.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21844651 - 2⁹ = 21844139 is a prime.

It is not a weakly prime, because it can be changed into another prime (21844601) 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 as a sum of consecutive naturals, namely, 10922325 + 10922326.

It is an arithmetic number, because the mean of its divisors is an integer number (10922326).

Almost surely, 2^21844651 is an apocalyptic number.

21844651 is a deficient number, since it is larger than the sum of its proper divisors (1).

21844651 is an equidigital number, since it uses as much as digits as its factorization.

21844651 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7680, while the sum is 31.

The square root of 21844651 is about 4673.8261627921. The cubic root of 21844651 is about 279.5428381723.

The spelling of 21844651 in words is "twenty-one million, eight hundred forty-four thousand, six hundred fifty-one".