1221131121 has 32 divisors (see below), whose sum is σ = 1960949760. Its totient is φ = 660306816.

The previous prime is 1221131113. The next prime is 1221131141. The reversal of 1221131121 is 1211311221.

It is not a de Polignac number, because 1221131121 - 2³ = 1221131113 is a prime.

It is a super-2 number, since 2×1221131121² = 2982322429349433282, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1221131121.

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 31 ways as a sum of consecutive naturals, for example, 660220 + ... + 662066.

It is an arithmetic number, because the mean of its divisors is an integer number (61279680).

Almost surely, 2^1221131121 is an apocalyptic number.

It is an amenable number.

1221131121 is a deficient number, since it is larger than the sum of its proper divisors (739818639).

1221131121 is a wasteful number, since it uses less digits than its factorization.

1221131121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3533.

The product of its digits is 24, while the sum is 15.

The square root of 1221131121 is about 34944.6865918125. The cubic root of 1221131121 is about 1068.8598566737.

Adding to 1221131121 its reverse (1211311221), we get a palindrome (2432442342).

It can be divided in two parts, 1 and 221131121, that added together give a palindrome (221131122).

The spelling of 1221131121 in words is "one billion, two hundred twenty-one million, one hundred thirty-one thousand, one hundred twenty-one".