2561634 has 24 divisors (see below), whose sum is σ = 5643612. Its totient is φ = 839520.

The previous prime is 2561633. The next prime is 2561651. The reversal of 2561634 is 4361652.

2561634 is a `hidden beast` number, since 25 + 6 + 1 + 634 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 2205225 + 356409 = 1485^2 + 597^2 .

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

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 2561598 and 2561607.

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 11 ways as a sum of consecutive naturals, for example, 69 + ... + 2264.

2^2561634 is an apocalyptic number.

2561634 is an abundant number, since it is smaller than the sum of its proper divisors (3081978).

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

2561634 is a wasteful number, since it uses less digits than its factorization.

2561634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2402 (or 2399 counting only the distinct ones).

The product of its digits is 4320, while the sum is 27.

The square root of 2561634 is about 1600.5105435454. The cubic root of 2561634 is about 136.8271747595.

The spelling of 2561634 in words is "two million, five hundred sixty-one thousand, six hundred thirty-four".