1666901643 has 32 divisors (see below), whose sum is σ = 2545724160. Its totient is φ = 960812160.

The previous prime is 1666901611. The next prime is 1666901657. The reversal of 1666901643 is 3461096661.

It is not a de Polignac number, because 1666901643 - 2⁵ = 1666901611 is a prime.

It is a super-2 number, since 2×1666901643² = 5557122174872198898, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1666901595 and 1666901604.

It is not an unprimeable number, because it can be changed into a prime (1666901683) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 51121 + ... + 77117.

It is an arithmetic number, because the mean of its divisors is an integer number (79553880).

Almost surely, 2^1666901643 is an apocalyptic number.

1666901643 is a deficient number, since it is larger than the sum of its proper divisors (878822517).

1666901643 is a wasteful number, since it uses less digits than its factorization.

1666901643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26107.

The product of its (nonzero) digits is 139968, while the sum is 42.

The square root of 1666901643 is about 40827.7068055506. The cubic root of 1666901643 is about 1185.6868179281.

It can be divided in two parts, 1666 and 901643, that added together give a palindrome (903309).

The spelling of 1666901643 in words is "one billion, six hundred sixty-six million, nine hundred one thousand, six hundred forty-three".