681761531 has 8 divisors (see below), whose sum is σ = 745462704. Its totient is φ = 618347520.

The previous prime is 681761513. The next prime is 681761533. The reversal of 681761531 is 135167186.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-681761531 is a prime.

It is a super-4 number, since 4×681761531⁴ (a number of 36 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (681761533) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 66806 + ... + 76331.

It is an arithmetic number, because the mean of its divisors is an integer number (93182838).

Almost surely, 2^681761531 is an apocalyptic number.

681761531 is a deficient number, since it is larger than the sum of its proper divisors (63701173).

681761531 is a wasteful number, since it uses less digits than its factorization.

681761531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 143581.

The product of its digits is 30240, while the sum is 38.

The square root of 681761531 is about 26110.5635902406. The cubic root of 681761531 is about 880.1246083016.

The spelling of 681761531 in words is "six hundred eighty-one million, seven hundred sixty-one thousand, five hundred thirty-one".