691284509725 has 12 divisors (see below), whose sum is σ = 861544030644. Its totient is φ = 550220357120.

The previous prime is 691284509717. The next prime is 691284509749. The reversal of 691284509725 is 527905482196.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 175585302841 + 515699206884 = 419029^2 + 718122^2 .

It is not a de Polignac number, because 691284509725 - 2³ = 691284509717 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 691284509725.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 70176244 + ... + 70186093.

It is an arithmetic number, because the mean of its divisors is an integer number (71795335887).

Almost surely, 2^691284509725 is an apocalyptic number.

It is an amenable number.

691284509725 is a deficient number, since it is larger than the sum of its proper divisors (170259520919).

691284509725 is a wasteful number, since it uses less digits than its factorization.

691284509725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140362544 (or 140362539 counting only the distinct ones).

The product of its (nonzero) digits is 10886400, while the sum is 58.

The spelling of 691284509725 in words is "six hundred ninety-one billion, two hundred eighty-four million, five hundred nine thousand, seven hundred twenty-five".