61666556605 has 8 divisors (see below), whose sum is σ = 77217253632. Its totient is φ = 47188321488.

The previous prime is 61666556603. The next prime is 61666556639. The reversal of 61666556605 is 50665566616.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 61666556605 - 2¹ = 61666556603 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 (61666556603) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 268115349 + ... + 268115578.

It is an arithmetic number, because the mean of its divisors is an integer number (9652156704).

Almost surely, 2^61666556605 is an apocalyptic number.

It is an amenable number.

61666556605 is a deficient number, since it is larger than the sum of its proper divisors (15550697027).

61666556605 is a wasteful number, since it uses less digits than its factorization.

61666556605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 536230955.

The product of its (nonzero) digits is 5832000, while the sum is 52.

The spelling of 61666556605 in words is "sixty-one billion, six hundred sixty-six million, five hundred fifty-six thousand, six hundred five".