20020921 has 4 divisors (see below), whose sum is σ = 20051172. Its totient is φ = 19990672.

The previous prime is 20020901. The next prime is 20020937. The reversal of 20020921 is 12902002.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 12924025 + 7096896 = 3595^2 + 2664^2 .

It is a cyclic number.

It is not a de Polignac number, because 20020921 - 2¹⁵ = 19988153 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20020895 and 20020904.

It is not an unprimeable number, because it can be changed into a prime (20020901) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14110 + ... + 15463.

It is an arithmetic number, because the mean of its divisors is an integer number (5012793).

Almost surely, 2^20020921 is an apocalyptic number.

It is an amenable number.

20020921 is a deficient number, since it is larger than the sum of its proper divisors (30251).

20020921 is an equidigital number, since it uses as much as digits as its factorization.

20020921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30250.

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 20020921 is about 4474.4743825392. The cubic root of 20020921 is about 271.5363758950.

Adding to 20020921 its reverse (12902002), we get a palindrome (32922923).

The spelling of 20020921 in words is "twenty million, twenty thousand, nine hundred twenty-one".