55581509 has 4 divisors (see below), whose sum is σ = 55605804. Its totient is φ = 55557216.

The previous prime is 55581497. The next prime is 55581523. The reversal of 55581509 is 90518555.

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 11730625 + 43850884 = 3425^2 + 6622^2 .

It is a cyclic number.

It is not a de Polignac number, because 55581509 - 2¹⁶ = 55515973 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 (55581529) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8312 + ... + 13425.

It is an arithmetic number, because the mean of its divisors is an integer number (13901451).

Almost surely, 2^55581509 is an apocalyptic number.

It is an amenable number.

55581509 is a deficient number, since it is larger than the sum of its proper divisors (24295).

55581509 is a wasteful number, since it uses less digits than its factorization.

55581509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24294.

The product of its (nonzero) digits is 45000, while the sum is 38.

The square root of 55581509 is about 7455.3007316942. The cubic root of 55581509 is about 381.6308234891.

The spelling of 55581509 in words is "fifty-five million, five hundred eighty-one thousand, five hundred nine".