121221111009 has 4 divisors (see below), whose sum is σ = 161628148016. Its totient is φ = 80814074004.

The previous prime is 121221110993. The next prime is 121221111043. The reversal of 121221111009 is 900111122121.

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, and also an emirpimes, since its reverse is a distinct semiprime: 900111122121 = 3 ⋅300037040707.

It is not a de Polignac number, because 121221111009 - 2⁴ = 121221110993 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (121221111049) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20203518499 + ... + 20203518504.

It is an arithmetic number, because the mean of its divisors is an integer number (40407037004).

Almost surely, 2^121221111009 is an apocalyptic number.

It is an amenable number.

121221111009 is a deficient number, since it is larger than the sum of its proper divisors (40407037007).

121221111009 is an equidigital number, since it uses as much as digits as its factorization.

121221111009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40407037006.

The product of its (nonzero) digits is 72, while the sum is 21.

The spelling of 121221111009 in words is "one hundred twenty-one billion, two hundred twenty-one million, one hundred eleven thousand, nine".