621641 has 2 divisors, whose sum is σ = 621642. Its totient is φ = 621640.

The previous prime is 621631. The next prime is 621671. The reversal of 621641 is 146126.

It is a happy number.

621641 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 can be written as a sum of positive squares in only one way, i.e., 495616 + 126025 = 704^2 + 355^2 .

It is a cyclic number.

It is not a de Polignac number, because 621641 - 2¹⁴ = 605257 is a prime.

It is equal to p₅₀₇₃₅ and since 621641 and 50735 have the same sum of digits, it is a Honaker prime.

It is a plaindrome in base 14.

It is not a weakly prime, because it can be changed into another prime (621611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 310820 + 310821.

It is an arithmetic number, because the mean of its divisors is an integer number (310821).

2⁶²¹⁶⁴¹ is an apocalyptic number.

It is an amenable number.

621641 is a deficient number, since it is larger than the sum of its proper divisors (1).

621641 is an equidigital number, since it uses as much as digits as its factorization.

621641 is an evil number, because the sum of its binary digits is even.

The product of its digits is 288, while the sum is 20.

The square root of 621641 is about 788.4421348457. The cubic root of 621641 is about 85.3453538703.

Adding to 621641 its reverse (146126), we get a palindrome (767767).

The spelling of 621641 in words is "six hundred twenty-one thousand, six hundred forty-one".