1212021121 has 4 divisors (see below), whose sum is σ = 1212620500. Its totient is φ = 1211421744.

The previous prime is 1212021113. The next prime is 1212021143. The reversal of 1212021121 is 1211202121.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 559984896 + 652036225 = 23664^2 + 25535^2 .

It is a cyclic number.

It is not a de Polignac number, because 1212021121 - 2³ = 1212021113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1212021221) 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, 296646 + ... + 300703.

It is an arithmetic number, because the mean of its divisors is an integer number (303155125).

Almost surely, 2^1212021121 is an apocalyptic number.

It is an amenable number.

1212021121 is a deficient number, since it is larger than the sum of its proper divisors (599379).

1212021121 is an equidigital number, since it uses as much as digits as its factorization.

1212021121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 599378.

The product of its (nonzero) digits is 16, while the sum is 13.

The square root of 1212021121 is about 34814.0937121735. The cubic root of 1212021121 is about 1066.1952155603.

Adding to 1212021121 its reverse (1211202121), we get a palindrome (2423223242).

The spelling of 1212021121 in words is "one billion, two hundred twelve million, twenty-one thousand, one hundred twenty-one".