55605501221 has 2 divisors, whose sum is σ = 55605501222. Its totient is φ = 55605501220.

The previous prime is 55605501187. The next prime is 55605501269. The reversal of 55605501221 is 12210550655.

55605501221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 40992076225 + 14613424996 = 202465^2 + 120886^2 .

It is a cyclic number.

It is not a de Polignac number, because 55605501221 - 2⁶ = 55605501157 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55605501421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27802750610 + 27802750611.

It is an arithmetic number, because the mean of its divisors is an integer number (27802750611).

Almost surely, 2^55605501221 is an apocalyptic number.

It is an amenable number.

55605501221 is a deficient number, since it is larger than the sum of its proper divisors (1).

55605501221 is an equidigital number, since it uses as much as digits as its factorization.

55605501221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15000, while the sum is 32.

The spelling of 55605501221 in words is "fifty-five billion, six hundred five million, five hundred one thousand, two hundred twenty-one".