689621 has 2 divisors, whose sum is σ = 689622. Its totient is φ = 689620.

The previous prime is 689603. The next prime is 689629. The reversal of 689621 is 126986.

689621 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 592900 + 96721 = 770^2 + 311^2 .

It is a cyclic number.

It is not a de Polignac number, because 689621 - 2¹⁸ = 427477 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (689629) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344810 + 344811.

It is an arithmetic number, because the mean of its divisors is an integer number (344811).

2⁶⁸⁹⁶²¹ is an apocalyptic number.

It is an amenable number.

689621 is a deficient number, since it is larger than the sum of its proper divisors (1).

689621 is an equidigital number, since it uses as much as digits as its factorization.

689621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5184, while the sum is 32.

The square root of 689621 is about 830.4342237649. The cubic root of 689621 is about 88.3493772527.

The spelling of 689621 in words is "six hundred eighty-nine thousand, six hundred twenty-one".