1661655500105 has 8 divisors (see below), whose sum is σ = 1993994405064. Its totient is φ = 1329319196800.

The previous prime is 1661655500101. The next prime is 1661655500129. The reversal of 1661655500105 is 5010055561661.

It can be written as a sum of positive squares in 4 ways, for example, as 173138377801 + 1488517122304 = 416099^2 + 1220048^2 .

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

It is not a de Polignac number, because 1661655500105 - 2² = 1661655500101 is a prime.

It is a super-2 number, since 2×1661655500105² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1661655500101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1270415 + ... + 2221995.

It is an arithmetic number, because the mean of its divisors is an integer number (249249300633).

Almost surely, 2^{1661655500105} is an apocalyptic number.

It is an amenable number.

1661655500105 is a deficient number, since it is larger than the sum of its proper divisors (332338904959).

1661655500105 is an equidigital number, since it uses as much as digits as its factorization.

1661655500105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1300827.

The product of its (nonzero) digits is 135000, while the sum is 41.

The spelling of 1661655500105 in words is "one trillion, six hundred sixty-one billion, six hundred fifty-five million, five hundred thousand, one hundred five".