5638821 has 4 divisors (see below), whose sum is σ = 7518432. Its totient is φ = 3759212.

The previous prime is 5638817. The next prime is 5638823. The reversal of 5638821 is 1288365.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 5638821 - 2² = 5638817 is a prime.

It is a D-number.

5638821 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (5638823) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 939801 + ... + 939806.

It is an arithmetic number, because the mean of its divisors is an integer number (1879608).

Almost surely, 2^5638821 is an apocalyptic number.

It is an amenable number.

5638821 is a deficient number, since it is larger than the sum of its proper divisors (1879611).

5638821 is a wasteful number, since it uses less digits than its factorization.

5638821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1879610.

The product of its digits is 11520, while the sum is 33.

The square root of 5638821 is about 2374.6201801551. The cubic root of 5638821 is about 177.9902048223.

The spelling of 5638821 in words is "five million, six hundred thirty-eight thousand, eight hundred twenty-one".