20021021200009 has 4 divisors (see below), whose sum is σ = 20080430758804. Its totient is φ = 19961611641216.

The previous prime is 20021021200001. The next prime is 20021021200091. The reversal of 20021021200009 is 90000212012002.

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 6224885280784 + 13796135919225 = 2494972^2 + 3714315^2 .

It is a cyclic number.

It is not a de Polignac number, because 20021021200009 - 2³ = 20021021200001 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20021021200001) 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, 29704778892 + ... + 29704779565.

It is an arithmetic number, because the mean of its divisors is an integer number (5020107689701).

Almost surely, 2^{20021021200009} is an apocalyptic number.

It is an amenable number.

20021021200009 is a deficient number, since it is larger than the sum of its proper divisors (59409558795).

20021021200009 is an equidigital number, since it uses as much as digits as its factorization.

20021021200009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59409558794.

The product of its (nonzero) digits is 144, while the sum is 19.

The spelling of 20021021200009 in words is "twenty trillion, twenty-one billion, twenty-one million, two hundred thousand, nine".