11212121 has 4 divisors (see below), whose sum is σ = 11472912. Its totient is φ = 10951332.

The previous prime is 11212081. The next prime is 11212127. The reversal of 11212121 is 12121211.

11212121 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 a cyclic number.

It is not a de Polignac number, because 11212121 - 2²² = 7017817 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11212127) 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, 130331 + ... + 130416.

It is an arithmetic number, because the mean of its divisors is an integer number (2868228).

Almost surely, 2^11212121 is an apocalyptic number.

It is an amenable number.

11212121 is a deficient number, since it is larger than the sum of its proper divisors (260791).

11212121 is an equidigital number, since it uses as much as digits as its factorization.

11212121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 260790.

The product of its digits is 8, while the sum is 11.

The square root of 11212121 is about 3348.4505371888. The cubic root of 11212121 is about 223.8184713928.

Adding to 11212121 its reverse (12121211), we get a palindrome (23333332).

The spelling of 11212121 in words is "eleven million, two hundred twelve thousand, one hundred twenty-one".