1231021320 has 32 divisors (see below), whose sum is σ = 3693064320. Its totient is φ = 328272320.

The previous prime is 1231021313. The next prime is 1231021327. The reversal of 1231021320 is 231201321.

It is an interprime number because it is at equal distance from previous prime (1231021313) and next prime (1231021327).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 1231021320.

It is not an unprimeable number, because it can be changed into a prime (1231021327) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5129136 + ... + 5129375.

It is an arithmetic number, because the mean of its divisors is an integer number (115408260).

Almost surely, 2^1231021320 is an apocalyptic number.

1231021320 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1231021320 is an abundant number, since it is smaller than the sum of its proper divisors (2462043000).

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

1231021320 is a wasteful number, since it uses less digits than its factorization.

1231021320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10258525 (or 10258521 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 15.

The square root of 1231021320 is about 35085.9134126504. The cubic root of 1231021320 is about 1071.7377416855.

Adding to 1231021320 its reverse (231201321), we get a palindrome (1462222641).

The spelling of 1231021320 in words is "one billion, two hundred thirty-one million, twenty-one thousand, three hundred twenty".