121221021220020 has 72 divisors (see below), whose sum is σ = 389333397575304. Its totient is φ = 30424099442688.

The previous prime is 121221021219979. The next prime is 121221021220051. The reversal of 121221021220020 is 20022120122121.

It is a happy number.

121221021220020 is a `hidden beast` number, since 1 + 21 + 2 + 210 + 212 + 200 + 20 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 9350165302416 + 111870855917604 = 3057804^2 + 10576902^2 .

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 = 121221021219975 and 121221021220002.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (31) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 19807353349 + ... + 19807359468.

It is an arithmetic number, because the mean of its divisors is an integer number (5407408299657).

Almost surely, 2^{121221021220020} is an apocalyptic number.

121221021220020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

121221021220020 is an abundant number, since it is smaller than the sum of its proper divisors (268112376355284).

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

121221021220020 is a wasteful number, since it uses less digits than its factorization.

121221021220020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39614712849 (or 39614712844 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 121221021220020 its reverse (20022120122121), we get a palindrome (141243141342141).

The spelling of 121221021220020 in words is "one hundred twenty-one trillion, two hundred twenty-one billion, twenty-one million, two hundred twenty thousand, twenty".