55120809586921 has 45 divisors (see below), whose sum is σ = 60289054317411. Its totient is φ = 50395462816608.

The previous prime is 55120809586919. The next prime is 55120809586933. The reversal of 55120809586921 is 12968590802155.

The square root of 55120809586921 is 7424339.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 7 ways, for example, as 35093716760025 + 20027092826896 = 5923995^2 + 4475164^2 .

It is not a de Polignac number, because 55120809586921 - 2¹ = 55120809586919 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 55120809586921.

It is not an unprimeable number, because it can be changed into a prime (55120809586621) 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 in 44 ways as a sum of consecutive naturals, for example, 247178518216 + ... + 247178518438.

Almost surely, 2^{55120809586921} is an apocalyptic number.

55120809586921 is the 7424339-th square number.

55120809586921 is the 3712170-th centered octagonal number.

It is an amenable number.

55120809586921 is a deficient number, since it is larger than the sum of its proper divisors (5168244730490).

55120809586921 is an frugal number, since it uses more digits than its factorization.

55120809586921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 892 (or 433 counting only the distinct ones).

The product of its (nonzero) digits is 15552000, while the sum is 61.

The spelling of 55120809586921 in words is "fifty-five trillion, one hundred twenty billion, eight hundred nine million, five hundred eighty-six thousand, nine hundred twenty-one".