20842121 has 8 divisors (see below), whose sum is σ = 21219264. Its totient is φ = 20467440.

The previous prime is 20842093. The next prime is 20842127. The reversal of 20842121 is 12124802.

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 20842121 - 2¹⁴ = 20825737 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20842093 and 20842102.

It is not an unprimeable number, because it can be changed into a prime (20842127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 26090 + ... + 26876.

It is an arithmetic number, because the mean of its divisors is an integer number (2652408).

Almost surely, 2^20842121 is an apocalyptic number.

It is an amenable number.

20842121 is a deficient number, since it is larger than the sum of its proper divisors (377143).

20842121 is an equidigital number, since it uses as much as digits as its factorization.

20842121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1231.

The product of its (nonzero) digits is 256, while the sum is 20.

The square root of 20842121 is about 4565.3171850376. The cubic root of 20842121 is about 275.1992869508.

Adding to 20842121 its reverse (12124802), we get a palindrome (32966923).

The spelling of 20842121 in words is "twenty million, eight hundred forty-two thousand, one hundred twenty-one".