681305120669 has 4 divisors (see below), whose sum is σ = 681474899196. Its totient is φ = 681135342144.

The previous prime is 681305120663. The next prime is 681305120737. The reversal of 681305120669 is 966021503186.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 533795355769 + 147509764900 = 730613^2 + 384070^2 .

It is a cyclic number.

It is not a de Polignac number, because 681305120669 - 2⁴ = 681305120653 is a prime.

It is a super-2 number, since 2×681305120669² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681305120663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 84883244 + ... + 84891269.

It is an arithmetic number, because the mean of its divisors is an integer number (170368724799).

Almost surely, 2^681305120669 is an apocalyptic number.

It is an amenable number.

681305120669 is a deficient number, since it is larger than the sum of its proper divisors (169778527).

681305120669 is a wasteful number, since it uses less digits than its factorization.

681305120669 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 169778526.

The product of its (nonzero) digits is 466560, while the sum is 47.

The spelling of 681305120669 in words is "six hundred eighty-one billion, three hundred five million, one hundred twenty thousand, six hundred sixty-nine".