20001221110020 has 96 divisors (see below), whose sum is σ = 57374979008256. Its totient is φ = 5203059712000.

The previous prime is 20001221109941. The next prime is 20001221110027. The reversal of 20001221110020 is 2001112210002.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 20001221109978 and 20001221110005.

It is not an unprimeable number, because it can be changed into a prime (20001221110027) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 25035745 + ... + 25822295.

It is an arithmetic number, because the mean of its divisors is an integer number (597656031336).

Almost surely, 2^{20001221110020} is an apocalyptic number.

20001221110020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20001221110020 is an abundant number, since it is smaller than the sum of its proper divisors (37373757898236).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20001221110020 is a wasteful number, since it uses less digits than its factorization.

20001221110020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 796941 (or 796939 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 20001221110020 its reverse (2001112210002), we get a palindrome (22002333320022).

The spelling of 20001221110020 in words is "twenty trillion, one billion, two hundred twenty-one million, one hundred ten thousand, twenty".