20001221022005 has 4 divisors (see below), whose sum is σ = 24001465226412. Its totient is φ = 16000976817600.

The previous prime is 20001221021987. The next prime is 20001221022059. The reversal of 20001221022005 is 50022012210002.

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 2566637897329 + 17434583124676 = 1602073^2 + 4175474^2 .

It is not a de Polignac number, because 20001221022005 - 2⁶ = 20001221021941 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2000122102196 + ... + 2000122102205.

It is an arithmetic number, because the mean of its divisors is an integer number (6000366306603).

Almost surely, 2^{20001221022005} is an apocalyptic number.

It is an amenable number.

20001221022005 is a deficient number, since it is larger than the sum of its proper divisors (4000244204407).

20001221022005 is an equidigital number, since it uses as much as digits as its factorization.

20001221022005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4000244204406.

The product of its (nonzero) digits is 160, while the sum is 17.

Adding to 20001221022005 its reverse (50022012210002), we get a palindrome (70023233232007).

The spelling of 20001221022005 in words is "twenty trillion, one billion, two hundred twenty-one million, twenty-two thousand, five".