1131221221 has 16 divisors (see below), whose sum is σ = 1289491840. Its totient is φ = 983741760.

The previous prime is 1131221209. The next prime is 1131221237. The reversal of 1131221221 is 1221221311.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1131221221 is a prime.

It is a super-2 number, since 2×1131221221² = 2559322901681461682, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1131221195 and 1131221204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1131221251) 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, 32056 + ... + 57358.

It is an arithmetic number, because the mean of its divisors is an integer number (80593240).

Almost surely, 2^1131221221 is an apocalyptic number.

It is an amenable number.

1131221221 is a deficient number, since it is larger than the sum of its proper divisors (158270619).

1131221221 is a wasteful number, since it uses less digits than its factorization.

1131221221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25516.

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

The square root of 1131221221 is about 33633.6322897186. The cubic root of 1131221221 is about 1041.9555234275.

Adding to 1131221221 its reverse (1221221311), we get a palindrome (2352442532).

The spelling of 1131221221 in words is "one billion, one hundred thirty-one million, two hundred twenty-one thousand, two hundred twenty-one".