121568809021 has 12 divisors (see below), whose sum is σ = 141485529276. Its totient is φ = 104016091520.

The previous prime is 121568809009. The next prime is 121568809031. The reversal of 121568809021 is 120908865121.

It can be written as a sum of positive squares in 2 ways, for example, as 79459716996 + 42109092025 = 281886^2 + 205205^2 .

It is not a de Polignac number, because 121568809021 - 2²¹ = 121566711869 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121568809031) 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, 29547970 + ... + 29552083.

It is an arithmetic number, because the mean of its divisors is an integer number (11790460773).

Almost surely, 2^121568809021 is an apocalyptic number.

121568809021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

121568809021 is a deficient number, since it is larger than the sum of its proper divisors (19916720255).

121568809021 is a wasteful number, since it uses less digits than its factorization.

121568809021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59100092 (or 59100081 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 43.

The spelling of 121568809021 in words is "one hundred twenty-one billion, five hundred sixty-eight million, eight hundred nine thousand, twenty-one".