646540320 has 96 divisors (see below), whose sum is σ = 2042288640. Its totient is φ = 171929600.

The previous prime is 646540267. The next prime is 646540339. The reversal of 646540320 is 23045646.

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

It is a Harshad number since it is a multiple of its sum of digits (30).

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 15 ways as a sum of consecutive naturals, for example, 190801 + ... + 194159.

It is an arithmetic number, because the mean of its divisors is an integer number (21273840).

Almost surely, 2^646540320 is an apocalyptic number.

646540320 is a gapful number since it is divisible by the number (60) 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 646540320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1021144320).

646540320 is an abundant number, since it is smaller than the sum of its proper divisors (1395748320).

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

646540320 is a wasteful number, since it uses less digits than its factorization.

646540320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3778 (or 3770 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 30.

The square root of 646540320 is about 25427.1571356296. The cubic root of 646540320 is about 864.6994935516.

Adding to 646540320 its reverse (23045646), we get a palindrome (669585966).

The spelling of 646540320 in words is "six hundred forty-six million, five hundred forty thousand, three hundred twenty".