321257664 has 336 divisors, whose sum is σ = 1180478208. Its totient is φ = 84354048.

The previous prime is 321257663. The next prime is 321257683. The reversal of 321257664 is 466752123.

321257664 is a `hidden beast` number, since 3 + 21 + 2 + 576 + 64 = 666.

It is a tau number, because it is divible by the number of its divisors (336).

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

Its product of digits (60480) is a multiple of the sum of its prime divisors (252).

It is not an unprimeable number, because it can be changed into a prime (321257663) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1415119 + ... + 1415345.

It is an arithmetic number, because the mean of its divisors is an integer number (3513328).

Almost surely, 2^321257664 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 321257664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (590239104).

321257664 is an abundant number, since it is smaller than the sum of its proper divisors (859220544).

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

321257664 is a wasteful number, since it uses less digits than its factorization.

321257664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 274 (or 252 counting only the distinct ones).

The product of its digits is 60480, while the sum is 36.

The square root of 321257664 is about 17923.6621258045. The cubic root of 321257664 is about 684.8852803072.

The spelling of 321257664 in words is "three hundred twenty-one million, two hundred fifty-seven thousand, six hundred sixty-four".