2563821 has 24 divisors (see below), whose sum is σ = 4226040. Its totient is φ = 1483776.

The previous prime is 2563819. The next prime is 2563837. The reversal of 2563821 is 1283652.

2563821 is a `hidden beast` number, since 2 + 5 + 638 + 21 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 617796 + 1946025 = 786^2 + 1395^2 .

It is not a de Polignac number, because 2563821 - 2¹ = 2563819 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2563811) 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, 1345 + ... + 2633.

It is an arithmetic number, because the mean of its divisors is an integer number (176085).

2^2563821 is an apocalyptic number.

It is an amenable number.

2563821 is a deficient number, since it is larger than the sum of its proper divisors (1662219).

2563821 is a wasteful number, since it uses less digits than its factorization.

2563821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1325 (or 1322 counting only the distinct ones).

The product of its digits is 2880, while the sum is 27.

The square root of 2563821 is about 1601.1936172743. The cubic root of 2563821 is about 136.8661025054.

The spelling of 2563821 in words is "two million, five hundred sixty-three thousand, eight hundred twenty-one".