641551 has 2 divisors, whose sum is σ = 641552. Its totient is φ = 641550.

The previous prime is 641549. The next prime is 641579. The reversal of 641551 is 155146.

641551 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 641551 - 2¹ = 641549 is a prime.

Together with 641549, it forms a pair of twin primes.

641551 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (641521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320775 + 320776.

It is an arithmetic number, because the mean of its divisors is an integer number (320776).

2⁶⁴¹⁵⁵¹ is an apocalyptic number.

641551 is a deficient number, since it is larger than the sum of its proper divisors (1).

641551 is an equidigital number, since it uses as much as digits as its factorization.

641551 is an evil number, because the sum of its binary digits is even.

The product of its digits is 600, while the sum is 22.

The square root of 641551 is about 800.9687884056. The cubic root of 641551 is about 86.2469466118.

Adding to 641551 its reverse (155146), we get a palindrome (796697).

The spelling of 641551 in words is "six hundred forty-one thousand, five hundred fifty-one".