641638 has 16 divisors (see below), whose sum is σ = 1013760. Its totient is φ = 304200.

The previous prime is 641633. The next prime is 641639. The reversal of 641638 is 836146.

641638 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641633) by changing a digit.

641638 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4833 + ... + 4963.

It is an arithmetic number, because the mean of its divisors is an integer number (63360).

2⁶⁴¹⁶³⁸ is an apocalyptic number.

641638 is a deficient number, since it is larger than the sum of its proper divisors (372122).

641638 is a wasteful number, since it uses less digits than its factorization.

641638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 243.

The product of its digits is 3456, while the sum is 28.

The square root of 641638 is about 801.0230957969. The cubic root of 641638 is about 86.2508450523.

The spelling of 641638 in words is "six hundred forty-one thousand, six hundred thirty-eight".