2581656 has 96 divisors (see below), whose sum is σ = 8171520. Its totient is φ = 665280.

The previous prime is 2581651. The next prime is 2581669. The reversal of 2581656 is 6561852.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is an alternating number because its digits alternate between even and odd.

Its product of digits (14400) is a multiple of the sum of its prime divisors (150).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2581651) 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, 20265 + ... + 20391.

It is an arithmetic number, because the mean of its divisors is an integer number (85120).

2^2581656 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 2581656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4085760).

2581656 is an abundant number, since it is smaller than the sum of its proper divisors (5589864).

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

2581656 is a wasteful number, since it uses less digits than its factorization.

2581656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165 (or 150 counting only the distinct ones).

The product of its digits is 14400, while the sum is 33.

The square root of 2581656 is about 1606.7532480129. The cubic root of 2581656 is about 137.1827351790.

The spelling of 2581656 in words is "two million, five hundred eighty-one thousand, six hundred fifty-six".