521000681 has 2 divisors, whose sum is σ = 521000682. Its totient is φ = 521000680.

The previous prime is 521000671. The next prime is 521000699. The reversal of 521000681 is 186000125.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 511483456 + 9517225 = 22616^2 + 3085^2 .

It is a cyclic number.

It is not a de Polignac number, because 521000681 - 2⁶ = 521000617 is a prime.

It is a super-2 number, since 2×521000681² = 542883419204927522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (521000671) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 260500340 + 260500341.

It is an arithmetic number, because the mean of its divisors is an integer number (260500341).

Almost surely, 2^521000681 is an apocalyptic number.

It is an amenable number.

521000681 is a deficient number, since it is larger than the sum of its proper divisors (1).

521000681 is an equidigital number, since it uses as much as digits as its factorization.

521000681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 480, while the sum is 23.

The square root of 521000681 is about 22825.4393385976. The cubic root of 521000681 is about 804.6606498882.

The spelling of 521000681 in words is "five hundred twenty-one million, six hundred eighty-one", and thus it is an aban number.