21744859 has 2 divisors, whose sum is σ = 21744860. Its totient is φ = 21744858.

The previous prime is 21744847. The next prime is 21744907. The reversal of 21744859 is 95844712.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21744859 - 2⁹ = 21744347 is a prime.

It is not a weakly prime, because it can be changed into another prime (21744839) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10872429 + 10872430.

It is an arithmetic number, because the mean of its divisors is an integer number (10872430).

Almost surely, 2^21744859 is an apocalyptic number.

21744859 is a deficient number, since it is larger than the sum of its proper divisors (1).

21744859 is an equidigital number, since it uses as much as digits as its factorization.

21744859 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 80640, while the sum is 40.

The square root of 21744859 is about 4663.1383209165. The cubic root of 21744859 is about 279.1165137300.

The spelling of 21744859 in words is "twenty-one million, seven hundred forty-four thousand, eight hundred fifty-nine".