2581666 has 8 divisors (see below), whose sum is σ = 3879324. Its totient is φ = 1288560.

The previous prime is 2581651. The next prime is 2581669. The reversal of 2581666 is 6661852.

It can be written as a sum of positive squares in 2 ways, for example, as 1809025 + 772641 = 1345^2 + 879^2 .

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

It is not an unprimeable number, because it can be changed into a prime (2581669) 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, 1596 + ... + 2776.

2^2581666 is an apocalyptic number.

2581666 is a deficient number, since it is larger than the sum of its proper divisors (1297658).

2581666 is a wasteful number, since it uses less digits than its factorization.

2581666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2276.

The product of its digits is 17280, while the sum is 34.

The square root of 2581666 is about 1606.7563598754. The cubic root of 2581666 is about 137.1829123038.

The spelling of 2581666 in words is "two million, five hundred eighty-one thousand, six hundred sixty-six".