641887 has 4 divisors (see below), whose sum is σ = 644920. Its totient is φ = 638856.

The previous prime is 641881. The next prime is 641891. The reversal of 641887 is 788146.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 788146 = 2 ⋅394073.

It is a cyclic number.

It is not a de Polignac number, because 641887 - 2¹¹ = 639839 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641881) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1173 + ... + 1630.

It is an arithmetic number, because the mean of its divisors is an integer number (161230).

2⁶⁴¹⁸⁸⁷ is an apocalyptic number.

641887 is a deficient number, since it is larger than the sum of its proper divisors (3033).

641887 is a wasteful number, since it uses less digits than its factorization.

641887 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3032.

The product of its digits is 10752, while the sum is 34.

The square root of 641887 is about 801.1785069509. The cubic root of 641887 is about 86.2620007106.

The spelling of 641887 in words is "six hundred forty-one thousand, eight hundred eighty-seven".