5221021621561 has 2 divisors, whose sum is σ = 5221021621562. Its totient is φ = 5221021621560.

The previous prime is 5221021621553. The next prime is 5221021621573. The reversal of 5221021621561 is 1651261201225.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5214075399225 + 6946222336 = 2283435^2 + 83344^2 .

It is a cyclic number.

It is not a de Polignac number, because 5221021621561 - 2³ = 5221021621553 is a prime.

It is a super-4 number, since 4×5221021621561⁴ (a number of 52 digits) contains 4444 as substring.

It is not a weakly prime, because it can be changed into another prime (5221021621591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2610510810780 + 2610510810781.

It is an arithmetic number, because the mean of its divisors is an integer number (2610510810781).

Almost surely, 2^{5221021621561} is an apocalyptic number.

It is an amenable number.

5221021621561 is a deficient number, since it is larger than the sum of its proper divisors (1).

5221021621561 is an equidigital number, since it uses as much as digits as its factorization.

5221021621561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 14400, while the sum is 34.

Adding to 5221021621561 its reverse (1651261201225), we get a palindrome (6872282822786).

The spelling of 5221021621561 in words is "five trillion, two hundred twenty-one billion, twenty-one million, six hundred twenty-one thousand, five hundred sixty-one".