643512240 has 120 divisors (see below), whose sum is σ = 2469880608. Its totient is φ = 147087360.

The previous prime is 643512187. The next prime is 643512253. The reversal of 643512240 is 42215346.

643512240 is a `hidden beast` number, since 6 + 435 + 1 + 224 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (120).

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, 58801 + ... + 68880.

Almost surely, 2^643512240 is an apocalyptic number.

643512240 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

643512240 is an abundant number, since it is smaller than the sum of its proper divisors (1826368368).

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

643512240 is a wasteful number, since it uses less digits than its factorization.

643512240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127707 (or 127698 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 27.

The square root of 643512240 is about 25367.5430422420. The cubic root of 643512240 is about 863.3474367819.

Adding to 643512240 its reverse (42215346), we get a palindrome (685727586).

The spelling of 643512240 in words is "six hundred forty-three million, five hundred twelve thousand, two hundred forty".