689969561 has 2 divisors, whose sum is σ = 689969562. Its totient is φ = 689969560.

The previous prime is 689969557. The next prime is 689969569. The reversal of 689969561 is 165969986.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 680166400 + 9803161 = 26080^2 + 3131^2 .

It is a cyclic number.

It is not a de Polignac number, because 689969561 - 2² = 689969557 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 689969561.

It is not a weakly prime, because it can be changed into another prime (689969569) 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, 344984780 + 344984781.

It is an arithmetic number, because the mean of its divisors is an integer number (344984781).

Almost surely, 2^689969561 is an apocalyptic number.

It is an amenable number.

689969561 is a deficient number, since it is larger than the sum of its proper divisors (1).

689969561 is an equidigital number, since it uses as much as digits as its factorization.

689969561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6298560, while the sum is 59.

The square root of 689969561 is about 26267.2716702744. The cubic root of 689969561 is about 883.6425980432.

The spelling of 689969561 in words is "six hundred eighty-nine million, nine hundred sixty-nine thousand, five hundred sixty-one".