20021207 has 4 divisors (see below), whose sum is σ = 20274720. Its totient is φ = 19767696.

The previous prime is 20021203. The next prime is 20021213. The reversal of 20021207 is 70212002.

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

It is not a de Polignac number, because 20021207 - 2² = 20021203 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20021191 and 20021200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20021203) 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 3 ways as a sum of consecutive naturals, for example, 126638 + ... + 126795.

It is an arithmetic number, because the mean of its divisors is an integer number (5068680).

Almost surely, 2^20021207 is an apocalyptic number.

20021207 is a deficient number, since it is larger than the sum of its proper divisors (253513).

20021207 is an equidigital number, since it uses as much as digits as its factorization.

20021207 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 253512.

The product of its (nonzero) digits is 56, while the sum is 14.

The square root of 20021207 is about 4474.5063414862. The cubic root of 20021207 is about 271.5376688597.

Adding to 20021207 its reverse (70212002), we get a palindrome (90233209).

The spelling of 20021207 in words is "twenty million, twenty-one thousand, two hundred seven".