20360821 has 4 divisors (see below), whose sum is σ = 21927052. Its totient is φ = 18794592.

The previous prime is 20360779. The next prime is 20360833. The reversal of 20360821 is 12806302.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12806302 = 2 ⋅6403151.

It can be written as a sum of positive squares in 2 ways, for example, as 6027025 + 14333796 = 2455^2 + 3786^2 .

It is a cyclic number.

It is not a de Polignac number, because 20360821 - 2⁹ = 20360309 is a prime.

It is a super-3 number, since 3×20360821³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20360792 and 20360801.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20360861) 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, 783096 + ... + 783121.

It is an arithmetic number, because the mean of its divisors is an integer number (5481763).

Almost surely, 2^20360821 is an apocalyptic number.

It is an amenable number.

20360821 is a deficient number, since it is larger than the sum of its proper divisors (1566231).

20360821 is a wasteful number, since it uses less digits than its factorization.

20360821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1566230.

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 20360821 is about 4512.2966436173. The cubic root of 20360821 is about 273.0644071538.

The spelling of 20360821 in words is "twenty million, three hundred sixty thousand, eight hundred twenty-one".