321516640 has 48 divisors (see below), whose sum is σ = 766348128. Its totient is φ = 127461376.

The previous prime is 321516619. The next prime is 321516641. The reversal of 321516640 is 46615123.

It is a junction number, because it is equal to n+sod(n) for n = 321516599 and 321516608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (321516641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9189 + ... + 26971.

It is an arithmetic number, because the mean of its divisors is an integer number (15965586).

Almost surely, 2^321516640 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 321516640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (383174064).

321516640 is an abundant number, since it is smaller than the sum of its proper divisors (444831488).

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

321516640 is a wasteful number, since it uses less digits than its factorization.

321516640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17911 (or 17903 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 321516640 is about 17930.8850869108. The cubic root of 321516640 is about 685.0692667981.

It can be divided in two parts, 321 and 516640, that added together give a square (516961 = 719²).

The spelling of 321516640 in words is "three hundred twenty-one million, five hundred sixteen thousand, six hundred forty".