1661111103 has 8 divisors (see below), whose sum is σ = 2217509248. Its totient is φ = 1106060184.

The previous prime is 1661111093. The next prime is 1661111173. The reversal of 1661111103 is 3011111661.

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

It is not a de Polignac number, because 1661111103 - 2⁴ = 1661111087 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1661111103.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661111173) 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, 333925 + ... + 338862.

It is an arithmetic number, because the mean of its divisors is an integer number (277188656).

Almost surely, 2^1661111103 is an apocalyptic number.

1661111103 is a deficient number, since it is larger than the sum of its proper divisors (556398145).

1661111103 is an equidigital number, since it uses as much as digits as its factorization.

1661111103 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 673613.

The product of its (nonzero) digits is 108, while the sum is 21.

The square root of 1661111103 is about 40756.7307692852. The cubic root of 1661111103 is about 1184.3122652197.

Adding to 1661111103 its reverse (3011111661), we get a palindrome (4672222764).

The spelling of 1661111103 in words is "one billion, six hundred sixty-one million, one hundred eleven thousand, one hundred three".