687161680 has 20 divisors (see below), whose sum is σ = 1597651092. Its totient is φ = 274864640.

The previous prime is 687161663. The next prime is 687161687. The reversal of 687161680 is 86161786.

It can be written as a sum of positive squares in 2 ways, for example, as 480837184 + 206324496 = 21928^2 + 14364^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (687161687) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4294681 + ... + 4294840.

Almost surely, 2^687161680 is an apocalyptic number.

It is an amenable number.

687161680 is an abundant number, since it is smaller than the sum of its proper divisors (910489412).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

687161680 is a wasteful number, since it uses less digits than its factorization.

687161680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8589534 (or 8589528 counting only the distinct ones).

The product of its (nonzero) digits is 96768, while the sum is 43.

The square root of 687161680 is about 26213.7689010947. The cubic root of 687161680 is about 882.4422858409.

The spelling of 687161680 in words is "six hundred eighty-seven million, one hundred sixty-one thousand, six hundred eighty".