20486821 has 4 divisors (see below), whose sum is σ = 20717100. Its totient is φ = 20256544.

The previous prime is 20486797. The next prime is 20486831. The reversal of 20486821 is 12868402.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10150596 + 10336225 = 3186^2 + 3215^2 .

It is a cyclic number.

It is not a de Polignac number, because 20486821 - 2¹¹ = 20484773 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 (20486831) 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, 115006 + ... + 115183.

It is an arithmetic number, because the mean of its divisors is an integer number (5179275).

Almost surely, 2^20486821 is an apocalyptic number.

It is an amenable number.

20486821 is a deficient number, since it is larger than the sum of its proper divisors (230279).

20486821 is an equidigital number, since it uses as much as digits as its factorization.

20486821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 230278.

The product of its (nonzero) digits is 6144, while the sum is 31.

The square root of 20486821 is about 4526.2369580039. The cubic root of 20486821 is about 273.6265224351.

It can be divided in two parts, 204 and 86821, that added together give a square (87025 = 295²).

The spelling of 20486821 in words is "twenty million, four hundred eighty-six thousand, eight hundred twenty-one".