641881 has 2 divisors, whose sum is σ = 641882. Its totient is φ = 641880.

The previous prime is 641873. The next prime is 641891. The reversal of 641881 is 188146.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 614656 + 27225 = 784^2 + 165^2 .

It is a cyclic number.

It is not a de Polignac number, because 641881 - 2³ = 641873 is a prime.

It is a super-2 number, since 2×641881² = 824022436322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (641821) 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 as a sum of consecutive naturals, namely, 320940 + 320941.

It is an arithmetic number, because the mean of its divisors is an integer number (320941).

2⁶⁴¹⁸⁸¹ is an apocalyptic number.

It is an amenable number.

641881 is a deficient number, since it is larger than the sum of its proper divisors (1).

641881 is an equidigital number, since it uses as much as digits as its factorization.

641881 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1536, while the sum is 28.

The square root of 641881 is about 801.1747624582. The cubic root of 641881 is about 86.2617319335.

The spelling of 641881 in words is "six hundred forty-one thousand, eight hundred eighty-one".