321720768 has 224 divisors, whose sum is σ = 1024128000. Its totient is φ = 98703360.

The previous prime is 321720743. The next prime is 321720779. The reversal of 321720768 is 867027123.

It is a Harshad number since it is a multiple of its sum of digits (36).

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 31 ways as a sum of consecutive naturals, for example, 1345993 + ... + 1346231.

It is an arithmetic number, because the mean of its divisors is an integer number (4572000).

Almost surely, 2^321720768 is an apocalyptic number.

321720768 is a gapful number since it is divisible by the number (38) 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 321720768, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (512064000).

321720768 is an abundant number, since it is smaller than the sum of its proper divisors (702407232).

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

321720768 is a wasteful number, since it uses less digits than its factorization.

321720768 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 320 (or 304 counting only the distinct ones).

The product of its (nonzero) digits is 28224, while the sum is 36.

The square root of 321720768 is about 17936.5762619291. The cubic root of 321720768 is about 685.2142175488.

The spelling of 321720768 in words is "three hundred twenty-one million, seven hundred twenty thousand, seven hundred sixty-eight".