21355343331457 has 2 divisors, whose sum is σ = 21355343331458. Its totient is φ = 21355343331456.

The previous prime is 21355343331433. The next prime is 21355343331499. The reversal of 21355343331457 is 75413334355312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16037333752896 + 5318009578561 = 4004664^2 + 2306081^2 .

It is a cyclic number.

It is not a de Polignac number, because 21355343331457 - 2¹¹ = 21355343329409 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21355343331457.

It is not a weakly prime, because it can be changed into another prime (21355343332457) 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, 10677671665728 + 10677671665729.

It is an arithmetic number, because the mean of its divisors is an integer number (10677671665729).

Almost surely, 2^{21355343331457} is an apocalyptic number.

It is an amenable number.

21355343331457 is a deficient number, since it is larger than the sum of its proper divisors (1).

21355343331457 is an equidigital number, since it uses as much as digits as its factorization.

21355343331457 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6804000, while the sum is 49.

Adding to 21355343331457 its reverse (75413334355312), we get a palindrome (96768677686769).

The spelling of 21355343331457 in words is "twenty-one trillion, three hundred fifty-five billion, three hundred forty-three million, three hundred thirty-one thousand, four hundred fifty-seven".