321961728 has 144 divisors (see below), whose sum is σ = 976018176. Its totient is φ = 93265920.

The previous prime is 321961727. The next prime is 321961763. The reversal of 321961728 is 827169123.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (321961727) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 193476 + ... + 195132.

It is an arithmetic number, because the mean of its divisors is an integer number (6777904).

Almost surely, 2^321961728 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 321961728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (488009088).

321961728 is an abundant number, since it is smaller than the sum of its proper divisors (654056448).

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

321961728 is a wasteful number, since it uses less digits than its factorization.

321961728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1710 (or 1696 counting only the distinct ones).

The product of its digits is 36288, while the sum is 39.

The square root of 321961728 is about 17943.2920056494. The cubic root of 321961728 is about 685.3852437208.

The spelling of 321961728 in words is "three hundred twenty-one million, nine hundred sixty-one thousand, seven hundred twenty-eight".