641778 has 8 divisors (see below), whose sum is σ = 1283568. Its totient is φ = 213924.

The previous prime is 641761. The next prime is 641789. The reversal of 641778 is 877146.

It is a sphenic number, since it is the product of 3 distinct primes.

641778 is an admirable number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 53476 + ... + 53487.

It is an arithmetic number, because the mean of its divisors is an integer number (160446).

2⁶⁴¹⁷⁷⁸ is an apocalyptic number.

641778 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

641778 is a wasteful number, since it uses less digits than its factorization.

641778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106968.

The product of its digits is 9408, while the sum is 33.

The square root of 641778 is about 801.1104792724. The cubic root of 641778 is about 86.2571176651.

The spelling of 641778 in words is "six hundred forty-one thousand, seven hundred seventy-eight".