2581644 has 72 divisors (see below), whose sum is σ = 6968640. Its totient is φ = 741312.

The previous prime is 2581643. The next prime is 2581651. The reversal of 2581644 is 4461852.

It is not an unprimeable number, because it can be changed into a prime (2581643) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 38499 + ... + 38565.

2^2581644 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2581644, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3484320).

2581644 is an abundant number, since it is smaller than the sum of its proper divisors (4386996).

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

2581644 is a wasteful number, since it uses less digits than its factorization.

2581644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 119 (or 104 counting only the distinct ones).

The product of its digits is 7680, while the sum is 30.

The square root of 2581644 is about 1606.7495137700. The cubic root of 2581644 is about 137.1825226287.

The spelling of 2581644 in words is "two million, five hundred eighty-one thousand, six hundred forty-four".