21841723 has 2 divisors, whose sum is σ = 21841724. Its totient is φ = 21841722.

The previous prime is 21841711. The next prime is 21841733. The reversal of 21841723 is 32714812.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21841723 - 2⁵ = 21841691 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21841691 and 21841700.

It is not a weakly prime, because it can be changed into another prime (21841733) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10920861 + 10920862.

It is an arithmetic number, because the mean of its divisors is an integer number (10920862).

Almost surely, 2^21841723 is an apocalyptic number.

21841723 is a deficient number, since it is larger than the sum of its proper divisors (1).

21841723 is an equidigital number, since it uses as much as digits as its factorization.

21841723 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2688, while the sum is 28.

The square root of 21841723 is about 4673.5129185656. The cubic root of 21841723 is about 279.5303478834.

The spelling of 21841723 in words is "twenty-one million, eight hundred forty-one thousand, seven hundred twenty-three".