21724783 has 2 divisors, whose sum is σ = 21724784. Its totient is φ = 21724782.

The previous prime is 21724757. The next prime is 21724819. The reversal of 21724783 is 38742712.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21724783 - 2⁵ = 21724751 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21725783) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10862391 + 10862392.

It is an arithmetic number, because the mean of its divisors is an integer number (10862392).

Almost surely, 2^21724783 is an apocalyptic number.

21724783 is a deficient number, since it is larger than the sum of its proper divisors (1).

21724783 is an equidigital number, since it uses as much as digits as its factorization.

21724783 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18816, while the sum is 34.

The square root of 21724783 is about 4660.9851962863. The cubic root of 21724783 is about 279.0305889219.

The spelling of 21724783 in words is "twenty-one million, seven hundred twenty-four thousand, seven hundred eighty-three".