20001221022100 has 36 divisors (see below), whose sum is σ = 43405242449184. Its totient is φ = 8000010467680.

The previous prime is 20001221022077. The next prime is 20001221022137. The reversal of 20001221022100 is 122012210002.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4289584 + ... + 7642183.

It is an arithmetic number, because the mean of its divisors is an integer number (1205701179144).

Almost surely, 2^{20001221022100} is an apocalyptic number.

20001221022100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20001221022100 is an abundant number, since it is smaller than the sum of its proper divisors (23404021427084).

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

20001221022100 is a wasteful number, since it uses less digits than its factorization.

20001221022100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11948544 (or 11948537 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 20001221022100 its reverse (122012210002), we get a palindrome (20123233232102).

The spelling of 20001221022100 in words is "twenty trillion, one billion, two hundred twenty-one million, twenty-two thousand, one hundred".