55005565661 has 4 divisors (see below), whose sum is σ = 55550175324. Its totient is φ = 54460956000.

The previous prime is 55005565487. The next prime is 55005565663. The reversal of 55005565661 is 16656550055.

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 43856317561 + 11149248100 = 209419^2 + 105590^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-55005565661 is a prime.

It is a super-2 number, since 2×55005565661² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55005565663) 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, 272304680 + ... + 272304881.

It is an arithmetic number, because the mean of its divisors is an integer number (13887543831).

Almost surely, 2^55005565661 is an apocalyptic number.

It is an amenable number.

55005565661 is a deficient number, since it is larger than the sum of its proper divisors (544609663).

55005565661 is a wasteful number, since it uses less digits than its factorization.

55005565661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 544609662.

The product of its (nonzero) digits is 675000, while the sum is 44.

The spelling of 55005565661 in words is "fifty-five billion, five million, five hundred sixty-five thousand, six hundred sixty-one".