21924317729 has 2 divisors, whose sum is σ = 21924317730. Its totient is φ = 21924317728.

The previous prime is 21924317713. The next prime is 21924317731. The reversal of 21924317729 is 92771342912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15183907729 + 6740410000 = 123223^2 + 82100^2 .

It is a cyclic number.

It is not a de Polignac number, because 21924317729 - 2⁴ = 21924317713 is a prime.

Together with 21924317731, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21924317929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10962158864 + 10962158865.

It is an arithmetic number, because the mean of its divisors is an integer number (10962158865).

Almost surely, 2^21924317729 is an apocalyptic number.

It is an amenable number.

21924317729 is a deficient number, since it is larger than the sum of its proper divisors (1).

21924317729 is an equidigital number, since it uses as much as digits as its factorization.

21924317729 is an evil number, because the sum of its binary digits is even.

The product of its digits is 381024, while the sum is 47.

The spelling of 21924317729 in words is "twenty-one billion, nine hundred twenty-four million, three hundred seventeen thousand, seven hundred twenty-nine".