687128914 has 4 divisors (see below), whose sum is σ = 1030693374. Its totient is φ = 343564456.

The previous prime is 687128909. The next prime is 687128917. The reversal of 687128914 is 419821786.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 419821786 = 2 ⋅209910893.

It can be written as a sum of positive squares in only one way, i.e., 545923225 + 141205689 = 23365^2 + 11883^2 .

It is a super-2 number, since 2×687128914² = 944292288909638792, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (687128917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 171782227 + ... + 171782230.

Almost surely, 2^687128914 is an apocalyptic number.

687128914 is a deficient number, since it is larger than the sum of its proper divisors (343564460).

687128914 is a wasteful number, since it uses less digits than its factorization.

687128914 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 343564459.

The product of its digits is 193536, while the sum is 46.

The square root of 687128914 is about 26213.1439167453. The cubic root of 687128914 is about 882.4282597563.

The spelling of 687128914 in words is "six hundred eighty-seven million, one hundred twenty-eight thousand, nine hundred fourteen".