21810734129 has 2 divisors, whose sum is σ = 21810734130. Its totient is φ = 21810734128.

The previous prime is 21810734123. The next prime is 21810734161. The reversal of 21810734129 is 92143701812.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16132810225 + 5677923904 = 127015^2 + 75352^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21810734129 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21810734092 and 21810734101.

It is not a weakly prime, because it can be changed into another prime (21810734123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10905367064 + 10905367065.

It is an arithmetic number, because the mean of its divisors is an integer number (10905367065).

Almost surely, 2^21810734129 is an apocalyptic number.

It is an amenable number.

21810734129 is a deficient number, since it is larger than the sum of its proper divisors (1).

21810734129 is an equidigital number, since it uses as much as digits as its factorization.

21810734129 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24192, while the sum is 38.

The spelling of 21810734129 in words is "twenty-one billion, eight hundred ten million, seven hundred thirty-four thousand, one hundred twenty-nine".