2581664 has 12 divisors (see below), whose sum is σ = 5082714. Its totient is φ = 1290816.

The previous prime is 2581651. The next prime is 2581669. The reversal of 2581664 is 4661852.

It can be written as a sum of positive squares in only one way, i.e., 2496400 + 85264 = 1580^2 + 292^2 .

It is a Harshad number since it is a multiple of its sum of digits (32), and also a Moran number because the ratio is a prime number: 80677 = 2581664 / (2 + 5 + 8 + 1 + 6 + 6 + 4).

It is a self number, because there is not a number n which added to its sum of digits gives 2581664.

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 as a sum of consecutive naturals, namely, 40307 + ... + 40370.

2^2581664 is an apocalyptic number.

It is an amenable number.

2581664 is a deficient number, since it is larger than the sum of its proper divisors (2501050).

2581664 is an equidigital number, since it uses as much as digits as its factorization.

2581664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80687 (or 80679 counting only the distinct ones).

The product of its digits is 11520, while the sum is 32.

The square root of 2581664 is about 1606.7557375034. The cubic root of 2581664 is about 137.1828768789.

The spelling of 2581664 in words is "two million, five hundred eighty-one thousand, six hundred sixty-four".