643415640 has 64 divisors (see below), whose sum is σ = 2205999360. Its totient is φ = 147066240.

The previous prime is 643415629. The next prime is 643415651. The reversal of 643415640 is 46514346.

It is an interprime number because it is at equal distance from previous prime (643415629) and next prime (643415651).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 382146 + ... + 383825.

It is an arithmetic number, because the mean of its divisors is an integer number (34468740).

Almost surely, 2^643415640 is an apocalyptic number.

643415640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

643415640 is an abundant number, since it is smaller than the sum of its proper divisors (1562583720).

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

643415640 is a wasteful number, since it uses less digits than its factorization.

643415640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 765992 (or 765988 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 33.

The square root of 643415640 is about 25365.6389629751. The cubic root of 643415640 is about 863.3042345289.

Adding to 643415640 its reverse (46514346), we get a palindrome (689929986).

The spelling of 643415640 in words is "six hundred forty-three million, four hundred fifteen thousand, six hundred forty".