55561011509 has 2 divisors, whose sum is σ = 55561011510. Its totient is φ = 55561011508.

The previous prime is 55561011503. The next prime is 55561011511. The reversal of 55561011509 is 90511016555.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 53002169284 + 2558842225 = 230222^2 + 50585^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-55561011509 is a prime.

Together with 55561011511, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55561011503) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27780505754 + 27780505755.

It is an arithmetic number, because the mean of its divisors is an integer number (27780505755).

Almost surely, 2^55561011509 is an apocalyptic number.

It is an amenable number.

55561011509 is a deficient number, since it is larger than the sum of its proper divisors (1).

55561011509 is an equidigital number, since it uses as much as digits as its factorization.

55561011509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 33750, while the sum is 38.

The spelling of 55561011509 in words is "fifty-five billion, five hundred sixty-one million, eleven thousand, five hundred nine".