55120564321561 has 2 divisors, whose sum is σ = 55120564321562. Its totient is φ = 55120564321560.

The previous prime is 55120564321507. The next prime is 55120564321607. The reversal of 55120564321561 is 16512346502155.

It is a happy number.

55120564321561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an a-pointer prime, because the next prime (55120564321607) can be obtained adding 55120564321561 to its sum of digits (46).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 47490622126336 + 7629942195225 = 6891344^2 + 2762235^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-55120564321561 is a prime.

It is a super-2 number, since 2×55120564321561² (a number of 28 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (55120564321961) 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, 27560282160780 + 27560282160781.

It is an arithmetic number, because the mean of its divisors is an integer number (27560282160781).

Almost surely, 2^{55120564321561} is an apocalyptic number.

It is an amenable number.

55120564321561 is a deficient number, since it is larger than the sum of its proper divisors (1).

55120564321561 is an equidigital number, since it uses as much as digits as its factorization.

55120564321561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1080000, while the sum is 46.

The spelling of 55120564321561 in words is "fifty-five trillion, one hundred twenty billion, five hundred sixty-four million, three hundred twenty-one thousand, five hundred sixty-one".