21724063541 has 2 divisors, whose sum is σ = 21724063542. Its totient is φ = 21724063540.

The previous prime is 21724063507. The next prime is 21724063597. The reversal of 21724063541 is 14536042712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11637878641 + 10086184900 = 107879^2 + 100430^2 .

It is a cyclic number.

It is not a de Polignac number, because 21724063541 - 2³⁰ = 20650321717 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21724060541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10862031770 + 10862031771.

It is an arithmetic number, because the mean of its divisors is an integer number (10862031771).

Almost surely, 2^21724063541 is an apocalyptic number.

It is an amenable number.

21724063541 is a deficient number, since it is larger than the sum of its proper divisors (1).

21724063541 is an equidigital number, since it uses as much as digits as its factorization.

21724063541 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 40320, while the sum is 35.

The spelling of 21724063541 in words is "twenty-one billion, seven hundred twenty-four million, sixty-three thousand, five hundred forty-one".