681772137993 has 6 divisors (see below), whose sum is σ = 984781977114. Its totient is φ = 454514758656.

The previous prime is 681772137979. The next prime is 681772138039. The reversal of 681772137993 is 399731277186.

681772137993 is a `hidden beast` number, since 6 + 8 + 177 + 2 + 1 + 379 + 93 = 666.

It can be written as a sum of positive squares in only one way, i.e., 664505389584 + 17266748409 = 815172^2 + 131403^2 .

It is not a de Polignac number, because 681772137993 - 2⁸ = 681772137737 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 681772137993.

It is not an unprimeable number, because it can be changed into a prime (681772137493) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 37876229880 + ... + 37876229897.

It is an arithmetic number, because the mean of its divisors is an integer number (164130329519).

Almost surely, 2^681772137993 is an apocalyptic number.

It is an amenable number.

681772137993 is a deficient number, since it is larger than the sum of its proper divisors (303009839121).

681772137993 is a wasteful number, since it uses less digits than its factorization.

681772137993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75752459783 (or 75752459780 counting only the distinct ones).

The product of its digits is 24004512, while the sum is 63.

The spelling of 681772137993 in words is "six hundred eighty-one billion, seven hundred seventy-two million, one hundred thirty-seven thousand, nine hundred ninety-three".