20782221 has 4 divisors (see below), whose sum is σ = 27709632. Its totient is φ = 13854812.

The previous prime is 20782217. The next prime is 20782231. The reversal of 20782221 is 12228702.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20782221 - 2² = 20782217 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 20782191 and 20782200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20782231) 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, 3463701 + ... + 3463706.

It is an arithmetic number, because the mean of its divisors is an integer number (6927408).

Almost surely, 2^20782221 is an apocalyptic number.

It is an amenable number.

20782221 is a deficient number, since it is larger than the sum of its proper divisors (6927411).

20782221 is an equidigital number, since it uses as much as digits as its factorization.

20782221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6927410.

The product of its (nonzero) digits is 896, while the sum is 24.

The square root of 20782221 is about 4558.7521318887. The cubic root of 20782221 is about 274.9353941897.

It can be divided in two parts, 207 and 82221, that added together give a palindrome (82428).

The spelling of 20782221 in words is "twenty million, seven hundred eighty-two thousand, two hundred twenty-one".