643254864 has 80 divisors (see below), whose sum is σ = 1902592512. Its totient is φ = 183452544.

The previous prime is 643254853. The next prime is 643254881. The reversal of 643254864 is 468452346.

It is a hoax number, since the sum of its digits (42) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent 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 15 ways as a sum of consecutive naturals, for example, 228087 + ... + 230889.

Almost surely, 2^643254864 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643254864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (951296256).

643254864 is an abundant number, since it is smaller than the sum of its proper divisors (1259337648).

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

643254864 is a wasteful number, since it uses less digits than its factorization.

643254864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3504 (or 3498 counting only the distinct ones).

The product of its digits is 552960, while the sum is 42.

The square root of 643254864 is about 25362.4695958418. The cubic root of 643254864 is about 863.2323213644.

The spelling of 643254864 in words is "six hundred forty-three million, two hundred fifty-four thousand, eight hundred sixty-four".