643668480 has 480 divisors, whose sum is σ = 2752573824. Its totient is φ = 135364608.

The previous prime is 643668479. The next prime is 643668481. The reversal of 643668480 is 84866346.

It is an interprime number because it is at equal distance from previous prime (643668479) and next prime (643668481).

It is a tau number, because it is divible by the number of its divisors (480).

It is a super-2 number, since 2×643668480² = 828618224291020800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (643668481) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2096487 + ... + 2096793.

Almost surely, 2^643668480 is an apocalyptic number.

643668480 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643668480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1376286912).

643668480 is an abundant number, since it is smaller than the sum of its proper divisors (2108905344).

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

643668480 is a wasteful number, since it uses less digits than its factorization.

643668480 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 356 (or 337 counting only the distinct ones).

The product of its (nonzero) digits is 663552, while the sum is 45.

The square root of 643668480 is about 25370.6223810138. The cubic root of 643668480 is about 863.4173025798.

The spelling of 643668480 in words is "six hundred forty-three million, six hundred sixty-eight thousand, four hundred eighty".