20421111 has 8 divisors (see below), whose sum is σ = 27264384. Its totient is φ = 13595960.

The previous prime is 20421103. The next prime is 20421179. The reversal of 20421111 is 11112402.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 20421111 - 2³ = 20421103 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20426111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1635 + ... + 6596.

It is an arithmetic number, because the mean of its divisors is an integer number (3408048).

Almost surely, 2^20421111 is an apocalyptic number.

20421111 is a deficient number, since it is larger than the sum of its proper divisors (6843273).

20421111 is an equidigital number, since it uses as much as digits as its factorization.

20421111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9061.

The product of its (nonzero) digits is 16, while the sum is 12.

The square root of 20421111 is about 4518.9723389284. The cubic root of 20421111 is about 273.3336633283. Note that the first 3 decimals are identical.

Adding to 20421111 its reverse (11112402), we get a palindrome (31533513).

The spelling of 20421111 in words is "twenty million, four hundred twenty-one thousand, one hundred eleven".