20327821 has 4 divisors (see below), whose sum is σ = 20400444. Its totient is φ = 20255200.

The previous prime is 20327807. The next prime is 20327849. The reversal of 20327821 is 12872302.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12872302 = 2 ⋅6436151.

It can be written as a sum of positive squares in 2 ways, for example, as 16080100 + 4247721 = 4010^2 + 2061^2 .

It is a cyclic number.

It is not a de Polignac number, because 20327821 - 2⁵ = 20327789 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20327861) 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 3 ways as a sum of consecutive naturals, for example, 35890 + ... + 36451.

It is an arithmetic number, because the mean of its divisors is an integer number (5100111).

Almost surely, 2^20327821 is an apocalyptic number.

It is an amenable number.

20327821 is a deficient number, since it is larger than the sum of its proper divisors (72623).

20327821 is an equidigital number, since it uses as much as digits as its factorization.

20327821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72622.

The product of its (nonzero) digits is 1344, while the sum is 25.

The square root of 20327821 is about 4508.6384862839. The cubic root of 20327821 is about 272.9168034444.

The spelling of 20327821 in words is "twenty million, three hundred twenty-seven thousand, eight hundred twenty-one".