641687 has 4 divisors (see below), whose sum is σ = 675480. Its totient is φ = 607896.

The previous prime is 641681. The next prime is 641701. The reversal of 641687 is 786146.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 786146 = 2 ⋅393073.

It is a cyclic number.

It is not a de Polignac number, because 641687 - 2⁶ = 641623 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 (641681) 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 3 ways as a sum of consecutive naturals, for example, 16868 + ... + 16905.

It is an arithmetic number, because the mean of its divisors is an integer number (168870).

2⁶⁴¹⁶⁸⁷ is an apocalyptic number.

641687 is a deficient number, since it is larger than the sum of its proper divisors (33793).

641687 is a wasteful number, since it uses less digits than its factorization.

641687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33792.

The product of its digits is 8064, while the sum is 32.

The square root of 641687 is about 801.0536810976. The cubic root of 641687 is about 86.2530405705.

The spelling of 641687 in words is "six hundred forty-one thousand, six hundred eighty-seven".