2563891 has 8 divisors (see below), whose sum is σ = 2843568. Its totient is φ = 2292000.

The previous prime is 2563877. The next prime is 2563901. The reversal of 2563891 is 1983652.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 2563891 - 2⁵ = 2563859 is a prime.

It is an Ulam number.

It is a Duffinian number.

2563891 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (2563811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1240 + ... + 2581.

It is an arithmetic number, because the mean of its divisors is an integer number (355446).

2^2563891 is an apocalyptic number.

2563891 is a deficient number, since it is larger than the sum of its proper divisors (279677).

2563891 is a wasteful number, since it uses less digits than its factorization.

2563891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3893.

The product of its digits is 12960, while the sum is 34.

The square root of 2563891 is about 1601.2154758183. The cubic root of 2563891 is about 136.8673481124.

The spelling of 2563891 in words is "two million, five hundred sixty-three thousand, eight hundred ninety-one".