21344042077 has 2 divisors, whose sum is σ = 21344042078. Its totient is φ = 21344042076.

The previous prime is 21344042063. The next prime is 21344042149. The reversal of 21344042077 is 77024044312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12847995801 + 8496046276 = 113349^2 + 92174^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21344042077 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21344042017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10672021038 + 10672021039.

It is an arithmetic number, because the mean of its divisors is an integer number (10672021039).

Almost surely, 2^21344042077 is an apocalyptic number.

It is an amenable number.

21344042077 is a deficient number, since it is larger than the sum of its proper divisors (1).

21344042077 is an equidigital number, since it uses as much as digits as its factorization.

21344042077 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 37632, while the sum is 34.

Adding to 21344042077 its reverse (77024044312), we get a palindrome (98368086389).

The spelling of 21344042077 in words is "twenty-one billion, three hundred forty-four million, forty-two thousand, seventy-seven".