61729616055421 has 8 divisors (see below), whose sum is σ = 65586931779960. Its totient is φ = 58098462165184.

The previous prime is 61729616055391. The next prime is 61729616055461. The reversal of 61729616055421 is 12455061692716.

61729616055421 = 5555610² + 5555611².

61729616055421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 30864802472100 + 30864813583321 = 5555610^2 + 5555611^2 .

It is not a de Polignac number, because 61729616055421 - 2¹¹ = 61729616053373 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61729616055461) 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 in 7 ways as a sum of consecutive naturals, for example, 6282268246 + ... + 6282278071.

It is an arithmetic number, because the mean of its divisors is an integer number (8198366472495).

Almost surely, 2^{61729616055421} is an apocalyptic number.

61729616055421 is the 5555611-st centered square number.

It is an amenable number.

61729616055421 is a deficient number, since it is larger than the sum of its proper divisors (3857315724539).

61729616055421 is an equidigital number, since it uses as much as digits as its factorization.

61729616055421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12564546368 (or 12564546334 counting only the distinct ones).

The product of its (nonzero) digits is 5443200, while the sum is 55.

The spelling of 61729616055421 in words is "sixty-one trillion, seven hundred twenty-nine billion, six hundred sixteen million, fifty-five thousand, four hundred twenty-one".