687128897 has 8 divisors (see below), whose sum is σ = 845697216. Its totient is φ = 543662352.

The previous prime is 687128789. The next prime is 687128909. The reversal of 687128897 is 798821786.

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 687128897 - 2¹⁶ = 687063361 is a prime.

It is a super-2 number, since 2×687128897² = 944292242184873218, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (687158897) 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, 3775343 + ... + 3775524.

It is an arithmetic number, because the mean of its divisors is an integer number (105712152).

Almost surely, 2^687128897 is an apocalyptic number.

It is an amenable number.

687128897 is a deficient number, since it is larger than the sum of its proper divisors (158568319).

687128897 is a wasteful number, since it uses less digits than its factorization.

687128897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7550887.

The product of its digits is 2709504, while the sum is 56.

The square root of 687128897 is about 26213.1435924805. The cubic root of 687128897 is about 882.4282524791.

The spelling of 687128897 in words is "six hundred eighty-seven million, one hundred twenty-eight thousand, eight hundred ninety-seven".