687698189 has 2 divisors, whose sum is σ = 687698190. Its totient is φ = 687698188.

The previous prime is 687698177. The next prime is 687698213. The reversal of 687698189 is 981896786.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 653569225 + 34128964 = 25565^2 + 5842^2 .

It is a cyclic number.

It is not a de Polignac number, because 687698189 - 2²⁸ = 419262733 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (687698149) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343849094 + 343849095.

It is an arithmetic number, because the mean of its divisors is an integer number (343849095).

Almost surely, 2^687698189 is an apocalyptic number.

It is an amenable number.

687698189 is a deficient number, since it is larger than the sum of its proper divisors (1).

687698189 is an equidigital number, since it uses as much as digits as its factorization.

687698189 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10450944, while the sum is 62.

The square root of 687698189 is about 26224.0002478646. Note that the first 3 decimals coincide. The cubic root of 687698189 is about 882.6718849205.

The spelling of 687698189 in words is "six hundred eighty-seven million, six hundred ninety-eight thousand, one hundred eighty-nine".