687938615081 has 4 divisors (see below), whose sum is σ = 687955190100. Its totient is φ = 687922040064.

The previous prime is 687938615059. The next prime is 687938615107. The reversal of 687938615081 is 180516839786.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 300102369856 + 387836245225 = 547816^2 + 622765^2 .

It is a cyclic number.

It is not a de Polignac number, because 687938615081 - 2¹⁰ = 687938614057 is a prime.

It is a super-2 number, since 2×687938615081² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (687938635081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8225096 + ... + 8308313.

It is an arithmetic number, because the mean of its divisors is an integer number (171988797525).

Almost surely, 2^687938615081 is an apocalyptic number.

It is an amenable number.

687938615081 is a deficient number, since it is larger than the sum of its proper divisors (16575019).

687938615081 is a wasteful number, since it uses less digits than its factorization.

687938615081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16575018.

The product of its (nonzero) digits is 17418240, while the sum is 62.

The spelling of 687938615081 in words is "six hundred eighty-seven billion, nine hundred thirty-eight million, six hundred fifteen thousand, eighty-one".