20311221 has 8 divisors (see below), whose sum is σ = 30950464. Its totient is φ = 11606400.

The previous prime is 20311211. The next prime is 20311273. The reversal of 20311221 is 12211302.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20311221 - 2⁵ = 20311189 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20311197 and 20311206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20311211) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 483580 + ... + 483621.

It is an arithmetic number, because the mean of its divisors is an integer number (3868808).

Almost surely, 2^20311221 is an apocalyptic number.

20311221 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

20311221 is a deficient number, since it is larger than the sum of its proper divisors (10639243).

20311221 is an equidigital number, since it uses as much as digits as its factorization.

20311221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 967211.

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 20311221 is about 4506.7971997861. The cubic root of 20311221 is about 272.8424939107.

Adding to 20311221 its reverse (12211302), we get a palindrome (32522523).

The spelling of 20311221 in words is "twenty million, three hundred eleven thousand, two hundred twenty-one".