321404640 has 96 divisors (see below), whose sum is σ = 1014957216. Its totient is φ = 85493760.

The previous prime is 321404639. The next prime is 321404647. The reversal of 321404640 is 46404123.

It is a tau number, because it is divible by the number of its divisors (96).

It is a super-2 number, since 2×321404640² = 206601885227059200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 321404640.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (321404647) 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 15 ways as a sum of consecutive naturals, for example, 316774 + ... + 317786.

It is an arithmetic number, because the mean of its divisors is an integer number (10572471).

Almost surely, 2^321404640 is an apocalyptic number.

321404640 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 321404640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (507478608).

321404640 is an abundant number, since it is smaller than the sum of its proper divisors (693552576).

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

321404640 is a wasteful number, since it uses less digits than its factorization.

321404640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1692 (or 1684 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 24.

The square root of 321404640 is about 17927.7617119372. The cubic root of 321404640 is about 684.9897098282.

Adding to 321404640 its reverse (46404123), we get a palindrome (367808763).

The spelling of 321404640 in words is "three hundred twenty-one million, four hundred four thousand, six hundred forty".