690509 has 2 divisors, whose sum is σ = 690510. Its totient is φ = 690508.

The previous prime is 690493. The next prime is 690511. The reversal of 690509 is 905096.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 532900 + 157609 = 730^2 + 397^2 .

It is a cyclic number.

It is not a de Polignac number, because 690509 - 2⁴ = 690493 is a prime.

Together with 690511, it forms a pair of twin primes.

It is a Chen prime.

It is an alternating number because its digits alternate between even and odd.

It is equal to p₅₅₈₄₇ and since 690509 and 55847 have the same sum of digits, it is a Honaker prime.

It is a plaindrome in base 6.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (690589) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345254 + 345255.

It is an arithmetic number, because the mean of its divisors is an integer number (345255).

2⁶⁹⁰⁵⁰⁹ is an apocalyptic number.

It is an amenable number.

690509 is a deficient number, since it is larger than the sum of its proper divisors (1).

690509 is an equidigital number, since it uses as much as digits as its factorization.

690509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2430, while the sum is 29.

The square root of 690509 is about 830.9687118057. The cubic root of 690509 is about 88.3872824194.

The spelling of 690509 in words is "six hundred ninety thousand, five hundred nine".