687058661 has 12 divisors (see below), whose sum is σ = 713264580. Its totient is φ = 661737600.

The previous prime is 687058651. The next prime is 687058667. The reversal of 687058661 is 166850786.

It can be written as a sum of positive squares in 6 ways, for example, as 211557025 + 475501636 = 14545^2 + 21806^2 .

It is a de Polignac number, because none of the positive numbers 2^k-687058661 is a prime.

It is a super-2 number, since 2×687058661² = 944099207310225842, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (687058667) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 135785 + ... + 140753.

It is an arithmetic number, because the mean of its divisors is an integer number (59438715).

Almost surely, 2^687058661 is an apocalyptic number.

It is an amenable number.

687058661 is a deficient number, since it is larger than the sum of its proper divisors (26205919).

687058661 is a wasteful number, since it uses less digits than its factorization.

687058661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5144 (or 5107 counting only the distinct ones).

The product of its (nonzero) digits is 483840, while the sum is 47.

The square root of 687058661 is about 26211.8038486480. The cubic root of 687058661 is about 882.3981851739.

The spelling of 687058661 in words is "six hundred eighty-seven million, fifty-eight thousand, six hundred sixty-one".