1666357111 has 4 divisors (see below), whose sum is σ = 1666557832. Its totient is φ = 1666156392.

The previous prime is 1666357109. The next prime is 1666357127. The reversal of 1666357111 is 1117536661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1117536661 = 19 ⋅58817719.

It is a cyclic number.

It is not a de Polignac number, because 1666357111 - 2¹ = 1666357109 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666357141) 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, 87345 + ... + 104698.

It is an arithmetic number, because the mean of its divisors is an integer number (416639458).

Almost surely, 2^1666357111 is an apocalyptic number.

1666357111 is a deficient number, since it is larger than the sum of its proper divisors (200721).

1666357111 is an equidigital number, since it uses as much as digits as its factorization.

1666357111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 200720.

The product of its digits is 22680, while the sum is 37.

The square root of 1666357111 is about 40821.0376031771. The cubic root of 1666357111 is about 1185.5576931865.

The spelling of 1666357111 in words is "one billion, six hundred sixty-six million, three hundred fifty-seven thousand, one hundred eleven".