2666689 has 9 divisors (see below), whose sum is σ = 2827489. Its totient is φ = 2514820.

The previous prime is 2666683. The next prime is 2666693. The reversal of 2666689 is 9866662.

2666689 = T₄₇₀ + T₄₇₁ + ... + T₄₉₂.

It is a happy number.

The square root of 2666689 is 1633.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 2666689 - 2⁷ = 2666561 is a prime.

It is a super-2 number, since 2×2666689² = 14222460445442, which contains 22 as substring.

It is a d-powerful number, because it can be written as 2²¹ + 6⁴ + 6⁵ + 6⁷ + 6⁷ + 8³ + 9² .

It is a Duffinian number.

It is a plaindrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (2666683) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 37524 + ... + 37594.

2^2666689 is an apocalyptic number.

2666689 is the 1633-rd square number.

2666689 is the 817-th centered octagonal number.

It is an amenable number.

2666689 is a deficient number, since it is larger than the sum of its proper divisors (160800).

2666689 is an frugal number, since it uses more digits than its factorization.

2666689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 188 (or 94 counting only the distinct ones).

The product of its digits is 186624, while the sum is 43.

The cubic root of 2666689 is about 138.6726419958.

Multiplying 2666689 by its product of digits (186624), we get a square (497668167936 = 705456²).

The spelling of 2666689 in words is "two million, six hundred sixty-six thousand, six hundred eighty-nine".