5642821 has 4 divisors (see below), whose sum is σ = 5694700. Its totient is φ = 5590944.

The previous prime is 5642803. The next prime is 5642839. The reversal of 5642821 is 1282465.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1282465 = 5 ⋅256493.

It is an interprime number because it is at equal distance from previous prime (5642803) and next prime (5642839).

It can be written as a sum of positive squares in 2 ways, for example, as 3572100 + 2070721 = 1890^2 + 1439^2 .

It is a cyclic number.

It is not a de Polignac number, because 5642821 - 2⁹ = 5642309 is a prime.

It is a Duffinian number.

5642821 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 5642821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (5642801) 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, 25776 + ... + 25993.

It is an arithmetic number, because the mean of its divisors is an integer number (1423675).

Almost surely, 2^5642821 is an apocalyptic number.

It is an amenable number.

5642821 is a deficient number, since it is larger than the sum of its proper divisors (51879).

5642821 is a wasteful number, since it uses less digits than its factorization.

5642821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51878.

The product of its digits is 3840, while the sum is 28.

The square root of 5642821 is about 2375.4622708012. The cubic root of 5642821 is about 178.0322817350.

The spelling of 5642821 in words is "five million, six hundred forty-two thousand, eight hundred twenty-one".