1661055 has 16 divisors (see below), whose sum is σ = 2899584. Its totient is φ = 805280.

The previous prime is 1661029. The next prime is 1661059. The reversal of 1661055 is 5501661.

It is not a de Polignac number, because 1661055 - 2¹³ = 1652863 is a prime.

It is a Smith number, since the sum of its digits (24) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661059) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4869 + ... + 5198.

It is an arithmetic number, because the mean of its divisors is an integer number (181224).

2^1661055 is an apocalyptic number.

1661055 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1661055 is a deficient number, since it is larger than the sum of its proper divisors (1238529).

1661055 is a wasteful number, since it uses less digits than its factorization.

1661055 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10086.

The product of its (nonzero) digits is 900, while the sum is 24.

The square root of 1661055 is about 1288.8192270447. The cubic root of 1661055 is about 118.4298931932.

Subtracting 1661055 from its reverse (5501661), we obtain a triangular number (3840606 = T₂₇₇₁).

It can be divided in two parts, 166 and 1055, that added together give a palindrome (1221).

The spelling of 1661055 in words is "one million, six hundred sixty-one thousand, fifty-five".