681732481 has 8 divisors (see below), whose sum is σ = 696349224. Its totient is φ = 667180800.

The previous prime is 681732431. The next prime is 681732497. The reversal of 681732481 is 184237186.

It can be written as a sum of positive squares in 4 ways, for example, as 596336400 + 85396081 = 24420^2 + 9241^2 .

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

It is a 6-Lehmer number, since φ(681732481) divides (681732481-1)⁶.

It is a cyclic number.

It is not a de Polignac number, because 681732481 - 2⁷ = 681732353 is a prime.

It is a super-2 number, since 2×681732481² = 929518351300830722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (681732421) 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 in 7 ways as a sum of consecutive naturals, for example, 5215 + ... + 37291.

It is an arithmetic number, because the mean of its divisors is an integer number (87043653).

Almost surely, 2^681732481 is an apocalyptic number.

It is an amenable number.

681732481 is a deficient number, since it is larger than the sum of its proper divisors (14616743).

681732481 is a wasteful number, since it uses less digits than its factorization.

681732481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32531.

The product of its digits is 64512, while the sum is 40.

The square root of 681732481 is about 26110.0072960541. The cubic root of 681732481 is about 880.1121073601.

The spelling of 681732481 in words is "six hundred eighty-one million, seven hundred thirty-two thousand, four hundred eighty-one".