687561161 has 8 divisors (see below), whose sum is σ = 799103040. Its totient is φ = 579349008.

The previous prime is 687561157. The next prime is 687561181. The reversal of 687561161 is 161165786.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 687561161 - 2² = 687561157 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (687561101) 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 7 ways as a sum of consecutive naturals, for example, 831986 + ... + 832811.

It is an arithmetic number, because the mean of its divisors is an integer number (99887880).

Almost surely, 2^687561161 is an apocalyptic number.

It is an amenable number.

687561161 is a deficient number, since it is larger than the sum of its proper divisors (111541879).

687561161 is a wasteful number, since it uses less digits than its factorization.

687561161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1664863.

The product of its digits is 60480, while the sum is 41.

The square root of 687561161 is about 26221.3874728245. The cubic root of 687561161 is about 882.6132551324.

The spelling of 687561161 in words is "six hundred eighty-seven million, five hundred sixty-one thousand, one hundred sixty-one".