55255122721 has 4 divisors (see below), whose sum is σ = 55317842244. Its totient is φ = 55192403200.

The previous prime is 55255122719. The next prime is 55255122737. The reversal of 55255122721 is 12722155255.

It is a happy number.

55255122721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 33920430625 + 21334692096 = 184175^2 + 146064^2 .

It is a cyclic number.

It is not a de Polignac number, because 55255122721 - 2¹ = 55255122719 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (55255182721) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31358440 + ... + 31360201.

It is an arithmetic number, because the mean of its divisors is an integer number (13829460561).

Almost surely, 2^55255122721 is an apocalyptic number.

It is an amenable number.

55255122721 is a deficient number, since it is larger than the sum of its proper divisors (62719523).

55255122721 is an equidigital number, since it uses as much as digits as its factorization.

55255122721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62719522.

The product of its digits is 70000, while the sum is 37.

Adding to 55255122721 its reverse (12722155255), we get a palindrome (67977277976).

The spelling of 55255122721 in words is "fifty-five billion, two hundred fifty-five million, one hundred twenty-two thousand, seven hundred twenty-one".