21493376990429 has 2 divisors, whose sum is σ = 21493376990430. Its totient is φ = 21493376990428.

The previous prime is 21493376990359. The next prime is 21493376990431. The reversal of 21493376990429 is 92409967339412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14016023464804 + 7477353525625 = 3743798^2 + 2734475^2 .

It is a cyclic number.

It is not a de Polignac number, because 21493376990429 - 2⁴⁰ = 20393865362653 is a prime.

Together with 21493376990431, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21493376990629) 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, 10746688495214 + 10746688495215.

It is an arithmetic number, because the mean of its divisors is an integer number (10746688495215).

Almost surely, 2^{21493376990429} is an apocalyptic number.

It is an amenable number.

21493376990429 is a deficient number, since it is larger than the sum of its proper divisors (1).

21493376990429 is an equidigital number, since it uses as much as digits as its factorization.

21493376990429 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 158723712, while the sum is 68.

The spelling of 21493376990429 in words is "twenty-one trillion, four hundred ninety-three billion, three hundred seventy-six million, nine hundred ninety thousand, four hundred twenty-nine".