643078881 has 27 divisors (see below), whose sum is σ = 949673361. Its totient is φ = 419336424.

The previous prime is 643078867. The next prime is 643078939. The reversal of 643078881 is 188870346.

The square root of 643078881 is 25359.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 643078881 - 2⁷ = 643078753 is a prime.

It is a super-2 number, since 2×643078881² = 827100894376424322, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (643078811) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 6010030 + ... + 6010136.

Almost surely, 2^643078881 is an apocalyptic number.

643078881 is the 25359-th square number.

643078881 is the 12680-th centered octagonal number.

It is an amenable number.

643078881 is a deficient number, since it is larger than the sum of its proper divisors (306594480).

643078881 is an equidigital number, since it uses as much as digits as its factorization.

643078881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 378 (or 189 counting only the distinct ones).

The product of its (nonzero) digits is 258048, while the sum is 45.

The cubic root of 643078881 is about 863.1535925547.

The spelling of 643078881 in words is "six hundred forty-three million, seventy-eight thousand, eight hundred eighty-one".