643475730 has 64 divisors (see below), whose sum is σ = 1587600000. Its totient is φ = 166817280.

The previous prime is 643475699. The next prime is 643475797. The reversal of 643475730 is 37574346.

It is a super-2 number, since 2×643475730² = 828122030198065800, which contains 22 as substring.

It is a Curzon number.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 428521 + ... + 430019.

It is an arithmetic number, because the mean of its divisors is an integer number (24806250).

Almost surely, 2^643475730 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643475730, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (793800000).

643475730 is an abundant number, since it is smaller than the sum of its proper divisors (944124270).

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

643475730 is a wasteful number, since it uses less digits than its factorization.

643475730 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1899.

The product of its (nonzero) digits is 211680, while the sum is 39.

The square root of 643475730 is about 25366.8234116927. The cubic root of 643475730 is about 863.3311089852.

The spelling of 643475730 in words is "six hundred forty-three million, four hundred seventy-five thousand, seven hundred thirty".