121211100020 has 36 divisors (see below), whose sum is σ = 268645448484. Its totient is φ = 45932624640.

The previous prime is 121211099983. The next prime is 121211100029. The reversal of 121211100020 is 20001112121.

It can be written as a sum of positive squares in 2 ways, for example, as 94436977636 + 26774122384 = 307306^2 + 163628^2 .

It is a junction number, because it is equal to n+sod(n) for n = 121211099974 and 121211100010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121211100029) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8386901 + ... + 8401340.

It is an arithmetic number, because the mean of its divisors is an integer number (7462373569).

Almost surely, 2^121211100020 is an apocalyptic number.

121211100020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

121211100020 is an abundant number, since it is smaller than the sum of its proper divisors (147434348464).

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

121211100020 is a wasteful number, since it uses less digits than its factorization.

121211100020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16788288 (or 16788267 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 121211100020 its reverse (20001112121), we get a palindrome (141212212141).

The spelling of 121211100020 in words is "one hundred twenty-one billion, two hundred eleven million, one hundred thousand, twenty".