1666420043 has 4 divisors (see below), whose sum is σ = 1666532808. Its totient is φ = 1666307280.

The previous prime is 1666420037. The next prime is 1666420057. The reversal of 1666420043 is 3400246661.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1666420043 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1666419991 and 1666420009.

It is not an unprimeable number, because it can be changed into a prime (1666420003) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30146 + ... + 65127.

It is an arithmetic number, because the mean of its divisors is an integer number (416633202).

Almost surely, 2^1666420043 is an apocalyptic number.

1666420043 is a deficient number, since it is larger than the sum of its proper divisors (112765).

1666420043 is an equidigital number, since it uses as much as digits as its factorization.

1666420043 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 112764.

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

The square root of 1666420043 is about 40821.8084239295. The cubic root of 1666420043 is about 1185.5726176740.

The spelling of 1666420043 in words is "one billion, six hundred sixty-six million, four hundred twenty thousand, forty-three".