2121666 has 8 divisors (see below), whose sum is σ = 4243344. Its totient is φ = 707220.

The previous prime is 2121661. The next prime is 2121667. The reversal of 2121666 is 6661212.

It is a sphenic number, since it is the product of 3 distinct primes.

2121666 is an admirable number.

It is a Smith number, since the sum of its digits (24) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (2121661) 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, 176800 + ... + 176811.

It is an arithmetic number, because the mean of its divisors is an integer number (530418).

2^2121666 is an apocalyptic number.

2121666 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

2121666 is a wasteful number, since it uses less digits than its factorization.

2121666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 353616.

The product of its digits is 864, while the sum is 24.

The square root of 2121666 is about 1456.5939722517. The cubic root of 2121666 is about 128.4968078461.

Adding to 2121666 its reverse (6661212), we get a palindrome (8782878).

The spelling of 2121666 in words is "two million, one hundred twenty-one thousand, six hundred sixty-six".