321217920 has 256 divisors, whose sum is σ = 1178712000. Its totient is φ = 82575360.

The previous prime is 321217909. The next prime is 321217937. The reversal of 321217920 is 29712123.

It is a Harshad number since it is a multiple of its sum of digits (27).

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, 500800 + ... + 501440.

Almost surely, 2^321217920 is an apocalyptic number.

321217920 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 321217920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (589356000).

321217920 is an abundant number, since it is smaller than the sum of its proper divisors (857494080).

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

321217920 is a wasteful number, since it uses less digits than its factorization.

321217920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 698 (or 680 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 27.

The square root of 321217920 is about 17922.5533895146. The cubic root of 321217920 is about 684.8570358935.

The spelling of 321217920 in words is "three hundred twenty-one million, two hundred seventeen thousand, nine hundred twenty".