21969869309429 has 2 divisors, whose sum is σ = 21969869309430. Its totient is φ = 21969869309428.

The previous prime is 21969869309393. The next prime is 21969869309447. The reversal of 21969869309429 is 92490396896912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21836788810225 + 133080499204 = 4672985^2 + 364802^2 .

It is a cyclic number.

It is not a de Polignac number, because 21969869309429 - 2³⁶ = 21901149832693 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21969869309429.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21969869309489) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10984934654714 + 10984934654715.

It is an arithmetic number, because the mean of its divisors is an integer number (10984934654715).

Almost surely, 2^{21969869309429} is an apocalyptic number.

It is an amenable number.

21969869309429 is a deficient number, since it is larger than the sum of its proper divisors (1).

21969869309429 is an equidigital number, since it uses as much as digits as its factorization.

21969869309429 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 816293376, while the sum is 77.

The spelling of 21969869309429 in words is "twenty-one trillion, nine hundred sixty-nine billion, eight hundred sixty-nine million, three hundred nine thousand, four hundred twenty-nine".