687221065 has 8 divisors (see below), whose sum is σ = 833931720. Its totient is φ = 543599232.

The previous prime is 687221063. The next prime is 687221081. The reversal of 687221065 is 560122786.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 18688329 + 668532736 = 4323^2 + 25856^2 .

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 687221065 - 2¹ = 687221063 is a prime.

It is not an unprimeable number, because it can be changed into a prime (687221063) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 771714 + ... + 772603.

It is an arithmetic number, because the mean of its divisors is an integer number (104241465).

Almost surely, 2^687221065 is an apocalyptic number.

It is an amenable number.

687221065 is a deficient number, since it is larger than the sum of its proper divisors (146710655).

687221065 is a wasteful number, since it uses less digits than its factorization.

687221065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1544411.

The product of its (nonzero) digits is 40320, while the sum is 37.

The square root of 687221065 is about 26214.9015828784. The cubic root of 687221065 is about 882.4677055382.

The spelling of 687221065 in words is "six hundred eighty-seven million, two hundred twenty-one thousand, sixty-five".