646042240 has 64 divisors (see below), whose sum is σ = 1547919360. Its totient is φ = 257836032.

The previous prime is 646042181. The next prime is 646042249. The reversal of 646042240 is 42240646.

It is a tau number, because it is divible by the number of its divisors (64).

It is a junction number, because it is equal to n+sod(n) for n = 646042199 and 646042208.

It is not an unprimeable number, because it can be changed into a prime (646042249) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 387649 + ... + 389311.

It is an arithmetic number, because the mean of its divisors is an integer number (24186240).

Almost surely, 2^646042240 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 646042240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (773959680).

646042240 is an abundant number, since it is smaller than the sum of its proper divisors (901877120).

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

646042240 is a wasteful number, since it uses less digits than its factorization.

646042240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2289 (or 2277 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 28.

The square root of 646042240 is about 25417.3609959807. The cubic root of 646042240 is about 864.4773882136.

Adding to 646042240 its reverse (42240646), we get a palindrome (688282886).

The spelling of 646042240 in words is "six hundred forty-six million, forty-two thousand, two hundred forty".