20101212121221 has 64 divisors (see below), whose sum is σ = 37736432332800. Its totient is φ = 10271004638400.

The previous prime is 20101212121217. The next prime is 20101212121261. The reversal of 20101212121221 is 12212121210102.

20101212121221 is a `hidden beast` number, since 201 + 0 + 121 + 2 + 121 + 221 = 666.

It is not a de Polignac number, because 20101212121221 - 2² = 20101212121217 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20101212121194 and 20101212121203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20101212121261) by changing a digit.

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 63 ways as a sum of consecutive naturals, for example, 79124761 + ... + 79378398.

It is an arithmetic number, because the mean of its divisors is an integer number (589631755200).

Almost surely, 2^{20101212121221} is an apocalyptic number.

20101212121221 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

20101212121221 is a deficient number, since it is larger than the sum of its proper divisors (17635220211579).

20101212121221 is a wasteful number, since it uses less digits than its factorization.

20101212121221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 158503247 (or 158503241 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

Adding to 20101212121221 its reverse (12212121210102), we get a palindrome (32313333331323).

The spelling of 20101212121221 in words is "twenty trillion, one hundred one billion, two hundred twelve million, one hundred twenty-one thousand, two hundred twenty-one".