1661043443 has 4 divisors (see below), whose sum is σ = 1661249160. Its totient is φ = 1660837728.

The previous prime is 1661043437. The next prime is 1661043473. The reversal of 1661043443 is 3443401661.

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

It is a cyclic number.

It is not a de Polignac number, because 1661043443 - 2⁴ = 1661043427 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1661043473) 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 3 ways as a sum of consecutive naturals, for example, 90230 + ... + 107067.

It is an arithmetic number, because the mean of its divisors is an integer number (415312290).

Almost surely, 2^1661043443 is an apocalyptic number.

1661043443 is a deficient number, since it is larger than the sum of its proper divisors (205717).

1661043443 is an equidigital number, since it uses as much as digits as its factorization.

1661043443 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 205716.

The product of its (nonzero) digits is 20736, while the sum is 32.

The square root of 1661043443 is about 40755.9007138844. The cubic root of 1661043443 is about 1184.2961852887.

The spelling of 1661043443 in words is "one billion, six hundred sixty-one million, forty-three thousand, four hundred forty-three".