121211210121 has 4 divisors (see below), whose sum is σ = 161614946832. Its totient is φ = 80807473412.

The previous prime is 121211210117. The next prime is 121211210137. The reversal of 121211210121 is 121012112121.

It is a happy number.

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: 121012112121 = 3 ⋅40337370707.

It is a cyclic number.

It is not a de Polignac number, because 121211210121 - 2² = 121211210117 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 121211210121.

It is not an unprimeable number, because it can be changed into a prime (121211210321) 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, 20201868351 + ... + 20201868356.

It is an arithmetic number, because the mean of its divisors is an integer number (40403736708).

Almost surely, 2^121211210121 is an apocalyptic number.

It is an amenable number.

121211210121 is a deficient number, since it is larger than the sum of its proper divisors (40403736711).

121211210121 is an equidigital number, since it uses as much as digits as its factorization.

121211210121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40403736710.

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 121211210121 its reverse (121012112121), we get a palindrome (242223322242).

It can be divided in two parts, 12121 and 1210121, that multiplied together give a palindrome (14667876641).

The spelling of 121211210121 in words is "one hundred twenty-one billion, two hundred eleven million, two hundred ten thousand, one hundred twenty-one".