1661043 has 4 divisors (see below), whose sum is σ = 2214728. Its totient is φ = 1107360.

The previous prime is 1661029. The next prime is 1661059. The reversal of 1661043 is 3401661.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 1661043 - 2¹² = 1656947 is a prime.

It is a D-number.

It is a Duffinian number.

1661043 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 276838 + ... + 276843.

It is an arithmetic number, because the mean of its divisors is an integer number (553682).

2^1661043 is an apocalyptic number.

1661043 is a deficient number, since it is larger than the sum of its proper divisors (553685).

1661043 is an equidigital number, since it uses as much as digits as its factorization.

1661043 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 553684.

The product of its (nonzero) digits is 432, while the sum is 21.

The square root of 1661043 is about 1288.8145716122. The cubic root of 1661043 is about 118.4296080005.

It can be divided in two parts, 16610 and 43, that added together give a triangular number (16653 = T₁₈₂).

The spelling of 1661043 in words is "one million, six hundred sixty-one thousand, forty-three".