641945 has 4 divisors (see below), whose sum is σ = 770340. Its totient is φ = 513552.

The previous prime is 641929. The next prime is 641959. The reversal of 641945 is 549146.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 491401 + 150544 = 701^2 + 388^2 .

It is a cyclic number.

It is not a de Polignac number, because 641945 - 2⁴ = 641929 is a prime.

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, 64190 + ... + 64199.

It is an arithmetic number, because the mean of its divisors is an integer number (192585).

2⁶⁴¹⁹⁴⁵ is an apocalyptic number.

It is an amenable number.

641945 is a deficient number, since it is larger than the sum of its proper divisors (128395).

641945 is a wasteful number, since it uses less digits than its factorization.

641945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128394.

The product of its digits is 4320, while the sum is 29.

The square root of 641945 is about 801.2147028107. The cubic root of 641945 is about 86.2645988031.

The spelling of 641945 in words is "six hundred forty-one thousand, nine hundred forty-five".