1221131131 has 16 divisors (see below), whose sum is σ = 1416048480. Its totient is φ = 1040711680.

The previous prime is 1221131113. The next prime is 1221131141. The reversal of 1221131131 is 1311311221.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 1221131131 - 2²³ = 1212742523 is a prime.

It is a super-2 number, since 2×1221131131² = 2982322478194678322, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1221131141) 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, 35355 + ... + 60763.

It is an arithmetic number, because the mean of its divisors is an integer number (88503030).

Almost surely, 2^1221131131 is an apocalyptic number.

1221131131 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1221131131 is a deficient number, since it is larger than the sum of its proper divisors (194917349).

1221131131 is a wasteful number, since it uses less digits than its factorization.

1221131131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25694.

The product of its digits is 36, while the sum is 16.

The square root of 1221131131 is about 34944.6867348958. The cubic root of 1221131131 is about 1068.8598595913.

Adding to 1221131131 its reverse (1311311221), we get a palindrome (2532442352).

The spelling of 1221131131 in words is "one billion, two hundred twenty-one million, one hundred thirty-one thousand, one hundred thirty-one".