1213221121 has 16 divisors (see below), whose sum is σ = 1405324800. Its totient is φ = 1025898048.

The previous prime is 1213221077. The next prime is 1213221137. The reversal of 1213221121 is 1211223121.

It is not a de Polignac number, because 1213221121 - 2⁷ = 1213220993 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1213221095 and 1213221104.

It is not an unprimeable number, because it can be changed into a prime (1213221521) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 179031 + ... + 185683.

It is an arithmetic number, because the mean of its divisors is an integer number (87832800).

Almost surely, 2^1213221121 is an apocalyptic number.

It is an amenable number.

1213221121 is a deficient number, since it is larger than the sum of its proper divisors (192103679).

1213221121 is a wasteful number, since it uses less digits than its factorization.

1213221121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7008.

The product of its digits is 48, while the sum is 16.

The square root of 1213221121 is about 34831.3238479389. The cubic root of 1213221121 is about 1066.5469729734.

Adding to 1213221121 its reverse (1211223121), we get a palindrome (2424444242).

The spelling of 1213221121 in words is "one billion, two hundred thirteen million, two hundred twenty-one thousand, one hundred twenty-one".