321612720 has 160 divisors (see below), whose sum is σ = 1171425024. Its totient is φ = 71961600.

The previous prime is 321612689. The next prime is 321612721. The reversal of 321612720 is 27216123.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is not an unprimeable number, because it can be changed into a prime (321612721) 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, 29635 + ... + 39005.

Almost surely, 2^321612720 is an apocalyptic number.

321612720 is a gapful number since it is divisible by the number (30) 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 321612720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (585712512).

321612720 is an abundant number, since it is smaller than the sum of its proper divisors (849812304).

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

321612720 is a wasteful number, since it uses less digits than its factorization.

321612720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9411 (or 9405 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 24.

The square root of 321612720 is about 17933.5640629519. The cubic root of 321612720 is about 685.1375005912.

Adding to 321612720 its reverse (27216123), we get a palindrome (348828843).

The spelling of 321612720 in words is "three hundred twenty-one million, six hundred twelve thousand, seven hundred twenty".