61661665555 has 16 divisors (see below), whose sum is σ = 84646482624. Its totient is φ = 42241328640.

The previous prime is 61661665519. The next prime is 61661665577. The reversal of 61661665555 is 55556616616.

61661665555 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 61661665555 - 2³³ = 53071730963 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 816586 + ... + 888895.

It is an arithmetic number, because the mean of its divisors is an integer number (5290405164).

Almost surely, 2^61661665555 is an apocalyptic number.

61661665555 is a deficient number, since it is larger than the sum of its proper divisors (22984817069).

61661665555 is a wasteful number, since it uses less digits than its factorization.

61661665555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1706526.

The product of its digits is 4860000, while the sum is 52.

The spelling of 61661665555 in words is "sixty-one billion, six hundred sixty-one million, six hundred sixty-five thousand, five hundred fifty-five".