1221312132 has 72 divisors (see below), whose sum is σ = 3209134656. Its totient is φ = 391293504.

The previous prime is 1221312091. The next prime is 1221312149. The reversal of 1221312132 is 2312131221.

1221312132 is a `hidden beast` number, since 1 + 221 + 312 + 132 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 105033 + ... + 116079.

Almost surely, 2^1221312132 is an apocalyptic number.

1221312132 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221312132, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1604567328).

1221312132 is an abundant number, since it is smaller than the sum of its proper divisors (1987822524).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1221312132 is a wasteful number, since it uses less digits than its factorization.

1221312132 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11177 (or 11172 counting only the distinct ones).

The product of its digits is 144, while the sum is 18.

The square root of 1221312132 is about 34947.2764604053. The cubic root of 1221312132 is about 1068.9126672275.

Adding to 1221312132 its reverse (2312131221), we get a palindrome (3533443353).

The spelling of 1221312132 in words is "one billion, two hundred twenty-one million, three hundred twelve thousand, one hundred thirty-two".