121211220121020 has 144 divisors (see below), whose sum is σ = 387384716339712. Its totient is φ = 30617473138560.

The previous prime is 121211220121009. The next prime is 121211220121027. The reversal of 121211220121020 is 20121022112121.

121211220121020 is a `hidden beast` number, since 1 + 2 + 1 + 211 + 220 + 1 + 210 + 20 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 121211220120984 and 121211220121002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121211220121027) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 141700146 + ... + 142552985.

It is an arithmetic number, because the mean of its divisors is an integer number (2690171641248).

Almost surely, 2^{121211220121020} is an apocalyptic number.

121211220121020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

121211220121020 is an abundant number, since it is smaller than the sum of its proper divisors (266173496218692).

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

121211220121020 is a wasteful number, since it uses less digits than its factorization.

121211220121020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 284253272 (or 284253267 counting only the distinct ones).

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

Adding to 121211220121020 its reverse (20121022112121), we get a palindrome (141332242233141).

The spelling of 121211220121020 in words is "one hundred twenty-one trillion, two hundred eleven billion, two hundred twenty million, one hundred twenty-one thousand, twenty".