646311240 has 96 divisors (see below), whose sum is σ = 2108316600. Its totient is φ = 171709440.

The previous prime is 646311233. The next prime is 646311269. The reversal of 646311240 is 42113646.

646311240 is a `hidden beast` number, since 6 + 4 + 631 + 1 + 24 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 352463076 + 293848164 = 18774^2 + 17142^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 97966 + ... + 104354.

Almost surely, 2^646311240 is an apocalyptic number.

646311240 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 646311240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1054158300).

646311240 is an abundant number, since it is smaller than the sum of its proper divisors (1462005360).

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

646311240 is a wasteful number, since it uses less digits than its factorization.

646311240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6687 (or 6680 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

The square root of 646311240 is about 25422.6521039800. The cubic root of 646311240 is about 864.5973556784.

Adding to 646311240 its reverse (42113646), we get a palindrome (688424886).

The spelling of 646311240 in words is "six hundred forty-six million, three hundred eleven thousand, two hundred forty".