1231221320 has 64 divisors (see below), whose sum is σ = 3206131200. Its totient is φ = 416782080.

The previous prime is 1231221317. The next prime is 1231221359. The reversal of 1231221320 is 231221321.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5711 + ... + 49950.

It is an arithmetic number, because the mean of its divisors is an integer number (50095800).

Almost surely, 2^1231221320 is an apocalyptic number.

1231221320 is a gapful number since it is divisible by the number (10) 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 1231221320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1603065600).

1231221320 is an abundant number, since it is smaller than the sum of its proper divisors (1974909880).

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

1231221320 is a wasteful number, since it uses less digits than its factorization.

1231221320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55758 (or 55754 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 1231221320 is about 35088.7634435869. The cubic root of 1231221320 is about 1071.7957791156.

Adding to 1231221320 its reverse (231221321), we get a palindrome (1462442641).

Subtracting from 1231221320 its reverse (231221321), we obtain a palindrome (999999999).

The spelling of 1231221320 in words is "one billion, two hundred thirty-one million, two hundred twenty-one thousand, three hundred twenty".