21203440129 has 2 divisors, whose sum is σ = 21203440130. Its totient is φ = 21203440128.

The previous prime is 21203440117. The next prime is 21203440201. The reversal of 21203440129 is 92104430212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20855692225 + 347747904 = 144415^2 + 18648^2 .

It is a cyclic number.

It is not a de Polignac number, because 21203440129 - 2²⁷ = 21069222401 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21203440097 and 21203440106.

It is not a weakly prime, because it can be changed into another prime (21203447129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10601720064 + 10601720065.

It is an arithmetic number, because the mean of its divisors is an integer number (10601720065).

Almost surely, 2^21203440129 is an apocalyptic number.

It is an amenable number.

21203440129 is a deficient number, since it is larger than the sum of its proper divisors (1).

21203440129 is an equidigital number, since it uses as much as digits as its factorization.

21203440129 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3456, while the sum is 28.

The spelling of 21203440129 in words is "twenty-one billion, two hundred three million, four hundred forty thousand, one hundred twenty-nine".