643826880 has 280 divisors, whose sum is σ = 2334554640. Its totient is φ = 168376320.

The previous prime is 643826867. The next prime is 643826903. The reversal of 643826880 is 88628346.

It is a happy number.

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

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 1529070 + ... + 1529490.

Almost surely, 2^643826880 is an apocalyptic number.

643826880 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 643826880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1167277320).

643826880 is an abundant number, since it is smaller than the sum of its proper divisors (1690727760).

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

643826880 is a wasteful number, since it uses less digits than its factorization.

643826880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 509 (or 490 counting only the distinct ones).

The product of its (nonzero) digits is 442368, while the sum is 45.

The square root of 643826880 is about 25373.7439097978. The cubic root of 643826880 is about 863.4881227238.

The spelling of 643826880 in words is "six hundred forty-three million, eight hundred twenty-six thousand, eight hundred eighty".