20642121 has 12 divisors (see below), whose sum is σ = 30921072. Its totient is φ = 13761252.

The previous prime is 20642099. The next prime is 20642129. The reversal of 20642121 is 12124602.

20642121 is a `hidden beast` number, since 2 + 0 + 642 + 1 + 21 = 666.

It is not a de Polignac number, because 20642121 - 2⁶ = 20642057 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20642094 and 20642103.

It is not an unprimeable number, because it can be changed into a prime (20642129) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 42231 + ... + 42716.

It is an arithmetic number, because the mean of its divisors is an integer number (2576756).

Almost surely, 2^20642121 is an apocalyptic number.

It is an amenable number.

20642121 is a deficient number, since it is larger than the sum of its proper divisors (10278951).

20642121 is an frugal number, since it uses more digits than its factorization.

20642121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84962 (or 84950 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 20642121 is about 4543.3601001902. The cubic root of 20642121 is about 274.3161897639.

Adding to 20642121 its reverse (12124602), we get a palindrome (32766723).

The spelling of 20642121 in words is "twenty million, six hundred forty-two thousand, one hundred twenty-one".