55207309 has 4 divisors (see below), whose sum is σ = 55297404. Its totient is φ = 55117216.

The previous prime is 55207297. The next prime is 55207343. The reversal of 55207309 is 90370255.

It is a happy number.

55207309 is nontrivially palindromic in base 15.

55207309 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 521284 + 54686025 = 722^2 + 7395^2 .

It is a cyclic number.

It is not a de Polignac number, because 55207309 - 2⁵ = 55207277 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 (55207709) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 44122 + ... + 45355.

It is an arithmetic number, because the mean of its divisors is an integer number (13824351).

Almost surely, 2^55207309 is an apocalyptic number.

It is an amenable number.

55207309 is a deficient number, since it is larger than the sum of its proper divisors (90095).

55207309 is an equidigital number, since it uses as much as digits as its factorization.

55207309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90094.

The product of its (nonzero) digits is 9450, while the sum is 31.

The square root of 55207309 is about 7430.1621112867. The cubic root of 55207309 is about 380.7724568627.

The spelling of 55207309 in words is "fifty-five million, two hundred seven thousand, three hundred nine".