1666766689 has 4 divisors (see below), whose sum is σ = 1904876224. Its totient is φ = 1428657156.

The previous prime is 1666766671. The next prime is 1666766711. The reversal of 1666766689 is 9866676661.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1666766689 - 2¹³ = 1666758497 is a prime.

It is a super-2 number, since 2×1666766689² = 5556222391120045442, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1666766609) 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, 119054757 + ... + 119054770.

It is an arithmetic number, because the mean of its divisors is an integer number (476219056).

Almost surely, 2^1666766689 is an apocalyptic number.

It is an amenable number.

1666766689 is a deficient number, since it is larger than the sum of its proper divisors (238109535).

1666766689 is an equidigital number, since it uses as much as digits as its factorization.

1666766689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 238109534.

The product of its digits is 23514624, while the sum is 61.

The square root of 1666766689 is about 40826.0540464052. The cubic root of 1666766689 is about 1185.6548189401.

The spelling of 1666766689 in words is "one billion, six hundred sixty-six million, seven hundred sixty-six thousand, six hundred eighty-nine".