20453821 has 2 divisors, whose sum is σ = 20453822. Its totient is φ = 20453820.

The previous prime is 20453809. The next prime is 20453863. The reversal of 20453821 is 12835402.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17264025 + 3189796 = 4155^2 + 1786^2 .

It is a cyclic number.

It is not a de Polignac number, because 20453821 - 2¹³ = 20445629 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20453921) 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 as a sum of consecutive naturals, namely, 10226910 + 10226911.

It is an arithmetic number, because the mean of its divisors is an integer number (10226911).

Almost surely, 2^20453821 is an apocalyptic number.

It is an amenable number.

20453821 is a deficient number, since it is larger than the sum of its proper divisors (1).

20453821 is an equidigital number, since it uses as much as digits as its factorization.

20453821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1920, while the sum is 25.

The square root of 20453821 is about 4522.5900764938. The cubic root of 20453821 is about 273.4795250412.

The spelling of 20453821 in words is "twenty million, four hundred fifty-three thousand, eight hundred twenty-one".