641815 has 8 divisors (see below), whose sum is σ = 803808. Its totient is φ = 491040.

The previous prime is 641813. The next prime is 641819. The reversal of 641815 is 518146.

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

It is not a de Polignac number, because 641815 - 2¹ = 641813 is a prime.

It is a Duffinian number.

641815 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 641815.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641813) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 2676 + ... + 2905.

It is an arithmetic number, because the mean of its divisors is an integer number (100476).

2⁶⁴¹⁸¹⁵ is an apocalyptic number.

641815 is a deficient number, since it is larger than the sum of its proper divisors (161993).

641815 is a wasteful number, since it uses less digits than its factorization.

641815 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5609.

The product of its digits is 960, while the sum is 25.

The square root of 641815 is about 801.1335718842. The cubic root of 641815 is about 86.2587752746.

The spelling of 641815 in words is "six hundred forty-one thousand, eight hundred fifteen".