641623 has 2 divisors, whose sum is σ = 641624. Its totient is φ = 641622.

The previous prime is 641581. The next prime is 641633. The reversal of 641623 is 326146.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 641623 - 2¹⁷ = 510551 is a prime.

641623 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 641594 and 641603.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (641633) 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, 320811 + 320812.

It is an arithmetic number, because the mean of its divisors is an integer number (320812).

2⁶⁴¹⁶²³ is an apocalyptic number.

641623 is a deficient number, since it is larger than the sum of its proper divisors (1).

641623 is an equidigital number, since it uses as much as digits as its factorization.

641623 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 864, while the sum is 22.

The square root of 641623 is about 801.0137327162. The cubic root of 641623 is about 86.2501729325.

Subtracting from 641623 its sum of digits (22), we obtain a square (641601 = 801²).

Adding to 641623 its reverse (326146), we get a palindrome (967769).

The spelling of 641623 in words is "six hundred forty-one thousand, six hundred twenty-three".