55155661565 has 4 divisors (see below), whose sum is σ = 66186793884. Its totient is φ = 44124529248.

The previous prime is 55155661541. The next prime is 55155661567. The reversal of 55155661565 is 56516655155.

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 18954130276 + 36201531289 = 137674^2 + 190267^2 .

It is a cyclic number.

It is not a de Polignac number, because 55155661565 - 2⁶ = 55155661501 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55155661567) 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, 5515566152 + ... + 5515566161.

It is an arithmetic number, because the mean of its divisors is an integer number (16546698471).

Almost surely, 2^55155661565 is an apocalyptic number.

It is an amenable number.

55155661565 is a deficient number, since it is larger than the sum of its proper divisors (11031132319).

55155661565 is a wasteful number, since it uses less digits than its factorization.

55155661565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11031132318.

The product of its digits is 3375000, while the sum is 50.

The spelling of 55155661565 in words is "fifty-five billion, one hundred fifty-five million, six hundred sixty-one thousand, five hundred sixty-five".