121131020021 has 4 divisors (see below), whose sum is σ = 132142930944. Its totient is φ = 110119109100.

The previous prime is 121131019939. The next prime is 121131020053. The reversal of 121131020021 is 120020131121.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 121131020021 - 2¹⁰ = 121131018997 is a prime.

It is a super-2 number, since 2×121131020021² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 121131019978 and 121131020005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121131320021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5505955445 + ... + 5505955466.

It is an arithmetic number, because the mean of its divisors is an integer number (33035732736).

Almost surely, 2^121131020021 is an apocalyptic number.

121131020021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

121131020021 is a deficient number, since it is larger than the sum of its proper divisors (11011910923).

121131020021 is a wasteful number, since it uses less digits than its factorization.

121131020021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11011910922.

The product of its (nonzero) digits is 24, while the sum is 14.

Adding to 121131020021 its reverse (120020131121), we get a palindrome (241151151142).

Subtracting from 121131020021 its reverse (120020131121), we obtain a square (1110888900 = 33330²).

The spelling of 121131020021 in words is "one hundred twenty-one billion, one hundred thirty-one million, twenty thousand, twenty-one".