121221100020 has 24 divisors (see below), whose sum is σ = 339419080224. Its totient is φ = 32325626656.

The previous prime is 121221100003. The next prime is 121221100067. The reversal of 121221100020 is 20001122121.

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 = 121221099969 and 121221100005.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1010175774 + ... + 1010175893.

It is an arithmetic number, because the mean of its divisors is an integer number (14142461676).

Almost surely, 2^121221100020 is an apocalyptic number.

121221100020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

121221100020 is an abundant number, since it is smaller than the sum of its proper divisors (218197980204).

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

121221100020 is a wasteful number, since it uses less digits than its factorization.

121221100020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2020351679 (or 2020351677 counting only the distinct ones).

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

Adding to 121221100020 its reverse (20001122121), we get a palindrome (141222222141).

The spelling of 121221100020 in words is "one hundred twenty-one billion, two hundred twenty-one million, one hundred thousand, twenty".