1666666669 has 4 divisors (see below), whose sum is σ = 1670282460. Its totient is φ = 1663050880.

The previous prime is 1666666667. The next prime is 1666666679. The reversal of 1666666669 is 9666666661.

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

It can be written as a sum of positive squares in 2 ways, for example, as 1251036900 + 415629769 = 35370^2 + 20387^2 .

It is a cyclic number.

It is not a de Polignac number, because 1666666669 - 2¹ = 1666666667 is a prime.

It is a super-2 number, since 2×1666666669² = 5555555571111111122, which contains 22 as substring.

It is a Duffinian number.

It is a plaindrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666666667) 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, 1807204 + ... + 1808125.

It is an arithmetic number, because the mean of its divisors is an integer number (417570615).

Almost surely, 2^1666666669 is an apocalyptic number.

It is an amenable number.

1666666669 is a deficient number, since it is larger than the sum of its proper divisors (3615791).

1666666669 is an equidigital number, since it uses as much as digits as its factorization.

1666666669 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3615790.

The product of its digits is 15116544, while the sum is 58.

The square root of 1666666669 is about 40824.8290749637. The cubic root of 1666666669 is about 1185.6311020500.

The spelling of 1666666669 in words is "one billion, six hundred sixty-six million, six hundred sixty-six thousand, six hundred sixty-nine".