646042340 has 12 divisors (see below), whose sum is σ = 1356688956. Its totient is φ = 258416928.

The previous prime is 646042337. The next prime is 646042349. The reversal of 646042340 is 43240646.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 495685696 + 150356644 = 22264^2 + 12262^2 .

It is not an unprimeable number, because it can be changed into a prime (646042349) 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 3 ways as a sum of consecutive naturals, for example, 16151039 + ... + 16151078.

It is an arithmetic number, because the mean of its divisors is an integer number (113057413).

Almost surely, 2^646042340 is an apocalyptic number.

It is an amenable number.

646042340 is an abundant number, since it is smaller than the sum of its proper divisors (710646616).

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

646042340 is a wasteful number, since it uses less digits than its factorization.

646042340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32302126 (or 32302124 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 29.

The square root of 646042340 is about 25417.3629631400. The cubic root of 646042340 is about 864.4774328174.

Adding to 646042340 its reverse (43240646), we get a palindrome (689282986).

The spelling of 646042340 in words is "six hundred forty-six million, forty-two thousand, three hundred forty".