684997665 has 16 divisors (see below), whose sum is σ = 1195632576. Its totient is φ = 332120000.

The previous prime is 684997657. The next prime is 684997721. The reversal of 684997665 is 566799486.

It is not a de Polignac number, because 684997665 - 2³ = 684997657 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 684997599 and 684997608.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2075586 + ... + 2075915.

It is an arithmetic number, because the mean of its divisors is an integer number (74727036).

Almost surely, 2^684997665 is an apocalyptic number.

It is an amenable number.

684997665 is a deficient number, since it is larger than the sum of its proper divisors (510634911).

684997665 is a wasteful number, since it uses less digits than its factorization.

684997665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4151520.

The product of its digits is 19595520, while the sum is 60.

The square root of 684997665 is about 26172.4600486848. The cubic root of 684997665 is about 881.5149803229.

The spelling of 684997665 in words is "six hundred eighty-four million, nine hundred ninety-seven thousand, six hundred sixty-five".