688969 has 2 divisors, whose sum is σ = 688970. Its totient is φ = 688968.

The previous prime is 688957. The next prime is 688979. The reversal of 688969 is 969886.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 518400 + 170569 = 720^2 + 413^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-688969 is a prime.

It is a super-2 number, since 2×688969² = 949356565922, which contains 22 as substring.

688969 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (688939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344484 + 344485.

It is an arithmetic number, because the mean of its divisors is an integer number (344485).

2⁶⁸⁸⁹⁶⁹ is an apocalyptic number.

It is an amenable number.

688969 is a deficient number, since it is larger than the sum of its proper divisors (1).

688969 is an equidigital number, since it uses as much as digits as its factorization.

688969 is an evil number, because the sum of its binary digits is even.

The product of its digits is 186624, while the sum is 46.

The square root of 688969 is about 830.0415652243. The cubic root of 688969 is about 88.3215252599.

The spelling of 688969 in words is "six hundred eighty-eight thousand, nine hundred sixty-nine".