21010505297 has 2 divisors, whose sum is σ = 21010505298. Its totient is φ = 21010505296.

The previous prime is 21010505213. The next prime is 21010505353. The reversal of 21010505297 is 79250501012.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16645128256 + 4365377041 = 129016^2 + 66071^2 .

It is a cyclic number.

It is not a de Polignac number, because 21010505297 - 2³² = 16715538001 is a prime.

It is not a weakly prime, because it can be changed into another prime (21010555297) 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, 10505252648 + 10505252649.

It is an arithmetic number, because the mean of its divisors is an integer number (10505252649).

Almost surely, 2^21010505297 is an apocalyptic number.

It is an amenable number.

21010505297 is a deficient number, since it is larger than the sum of its proper divisors (1).

21010505297 is an equidigital number, since it uses as much as digits as its factorization.

21010505297 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6300, while the sum is 32.

The spelling of 21010505297 in words is "twenty-one billion, ten million, five hundred five thousand, two hundred ninety-seven".