687098521 has 2 divisors, whose sum is σ = 687098522. Its totient is φ = 687098520.

The previous prime is 687098513. The next prime is 687098543. The reversal of 687098521 is 125890786.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 550559296 + 136539225 = 23464^2 + 11685^2 .

It is a cyclic number.

It is not a de Polignac number, because 687098521 - 2³ = 687098513 is a prime.

It is not a weakly prime, because it can be changed into another prime (687098561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343549260 + 343549261.

It is an arithmetic number, because the mean of its divisors is an integer number (343549261).

Almost surely, 2^687098521 is an apocalyptic number.

It is an amenable number.

687098521 is a deficient number, since it is larger than the sum of its proper divisors (1).

687098521 is an equidigital number, since it uses as much as digits as its factorization.

687098521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 241920, while the sum is 46.

The square root of 687098521 is about 26212.5641820864. The cubic root of 687098521 is about 882.4152490791.

The spelling of 687098521 in words is "six hundred eighty-seven million, ninety-eight thousand, five hundred twenty-one".