21053435281 has 2 divisors, whose sum is σ = 21053435282. Its totient is φ = 21053435280.

The previous prime is 21053435191. The next prime is 21053435321. The reversal of 21053435281 is 18253435012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11641331025 + 9412104256 = 107895^2 + 97016^2 .

It is a cyclic number.

It is not a de Polignac number, because 21053435281 - 2³¹ = 18905951633 is a prime.

It is a super-2 number, since 2×21053435281² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21053435581) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10526717640 + 10526717641.

It is an arithmetic number, because the mean of its divisors is an integer number (10526717641).

Almost surely, 2^21053435281 is an apocalyptic number.

It is an amenable number.

21053435281 is a deficient number, since it is larger than the sum of its proper divisors (1).

21053435281 is an equidigital number, since it uses as much as digits as its factorization.

21053435281 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 28800, while the sum is 34.

The spelling of 21053435281 in words is "twenty-one billion, fifty-three million, four hundred thirty-five thousand, two hundred eighty-one".