2561636 has 24 divisors (see below), whose sum is σ = 5589696. Its totient is φ = 997920.

The previous prime is 2561633. The next prime is 2561651. The reversal of 2561636 is 6361652.

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

It is a junction number, because it is equal to n+sod(n) for n = 2561599 and 2561608.

It is not an unprimeable number, because it can be changed into a prime (2561633) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3851 + ... + 4466.

It is an arithmetic number, because the mean of its divisors is an integer number (232904).

2^2561636 is an apocalyptic number.

It is an amenable number.

2561636 is an abundant number, since it is smaller than the sum of its proper divisors (3028060).

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

2561636 is a wasteful number, since it uses less digits than its factorization.

2561636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8339 (or 8337 counting only the distinct ones).

The product of its digits is 6480, while the sum is 29.

The square root of 2561636 is about 1600.5111683459. The cubic root of 2561636 is about 136.8272103688.

It can be divided in two parts, 25616 and 36, that added together give a palindrome (25652).

The spelling of 2561636 in words is "two million, five hundred sixty-one thousand, six hundred thirty-six".