687057661 has 8 divisors (see below), whose sum is σ = 695503800. Its totient is φ = 678627840.

The previous prime is 687057659. The next prime is 687057673. The reversal of 687057661 is 166750786.

It can be written as a sum of positive squares in 4 ways, for example, as 1612900 + 685444761 = 1270^2 + 26181^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 687057661 - 2¹ = 687057659 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (687057611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 95221 + ... + 102181.

It is an arithmetic number, because the mean of its divisors is an integer number (86937975).

Almost surely, 2^687057661 is an apocalyptic number.

It is an amenable number.

687057661 is a deficient number, since it is larger than the sum of its proper divisors (8446139).

687057661 is a wasteful number, since it uses less digits than its factorization.

687057661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8159.

The product of its (nonzero) digits is 423360, while the sum is 46.

The square root of 687057661 is about 26211.7847732656. The cubic root of 687057661 is about 882.3977570695.

The spelling of 687057661 in words is "six hundred eighty-seven million, fifty-seven thousand, six hundred sixty-one".