5211051221561 has 2 divisors, whose sum is σ = 5211051221562. Its totient is φ = 5211051221560.

The previous prime is 5211051221543. The next prime is 5211051221581. The reversal of 5211051221561 is 1651221501125.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4347370951225 + 863680270336 = 2085035^2 + 929344^2 .

It is a cyclic number.

It is not a de Polignac number, because 5211051221561 - 2¹⁴ = 5211051205177 is a prime.

It is a super-2 number, since 2×5211051221561² (a number of 26 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (5211051221581) 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, 2605525610780 + 2605525610781.

It is an arithmetic number, because the mean of its divisors is an integer number (2605525610781).

Almost surely, 2^{5211051221561} is an apocalyptic number.

It is an amenable number.

5211051221561 is a deficient number, since it is larger than the sum of its proper divisors (1).

5211051221561 is an equidigital number, since it uses as much as digits as its factorization.

5211051221561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6000, while the sum is 32.

Adding to 5211051221561 its reverse (1651221501125), we get a palindrome (6862272722686).

The spelling of 5211051221561 in words is "five trillion, two hundred eleven billion, fifty-one million, two hundred twenty-one thousand, five hundred sixty-one".