12321720 has 80 divisors (see below), whose sum is σ = 41425560. Its totient is φ = 3284928.

The previous prime is 12321713. The next prime is 12321733. The reversal of 12321720 is 2712321.

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

It is a junction number, because it is equal to n+sod(n) for n = 12321693 and 12321702.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1339 + ... + 5141.

Almost surely, 2^12321720 is an apocalyptic number.

12321720 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 12321720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20712780).

12321720 is an abundant number, since it is smaller than the sum of its proper divisors (29103840).

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

12321720 is a wasteful number, since it uses less digits than its factorization.

12321720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3826 (or 3813 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 18.

The square root of 12321720 is about 3510.2307616452. The cubic root of 12321720 is about 230.9708177000.

It can be divided in two parts, 12321 and 720, that added together give a triangular number (13041 = T₁₆₁).

The spelling of 12321720 in words is "twelve million, three hundred twenty-one thousand, seven hundred twenty".