643734650 has 24 divisors (see below), whose sum is σ = 1289451324. Its totient is φ = 237686400.

The previous prime is 643734643. The next prime is 643734691. The reversal of 643734650 is 56437346.

643734650 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 6 ways, for example, as 158281561 + 485453089 = 12581^2 + 22033^2 .

It is a super-2 number, since 2×643734650² = 828788599221245000, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 494531 + ... + 495830.

Almost surely, 2^643734650 is an apocalyptic number.

643734650 is an abundant number, since it is smaller than the sum of its proper divisors (645716674).

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

643734650 is a wasteful number, since it uses less digits than its factorization.

643734650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 990386 (or 990381 counting only the distinct ones).

The product of its (nonzero) digits is 181440, while the sum is 38.

The square root of 643734650 is about 25371.9264148389. The cubic root of 643734650 is about 863.4468883925.

The spelling of 643734650 in words is "six hundred forty-three million, seven hundred thirty-four thousand, six hundred fifty".