684987305 has 4 divisors (see below), whose sum is σ = 821984772. Its totient is φ = 547989840.

The previous prime is 684987299. The next prime is 684987349. The reversal of 684987305 is 503789486.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 430521001 + 254466304 = 20749^2 + 15952^2 .

It is not a de Polignac number, because 684987305 - 2⁶ = 684987241 is a prime.

It is a super-2 number, since 2×684987305² = 938415216022326050, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 68498726 + ... + 68498735.

It is an arithmetic number, because the mean of its divisors is an integer number (205496193).

Almost surely, 2^684987305 is an apocalyptic number.

It is an amenable number.

684987305 is a deficient number, since it is larger than the sum of its proper divisors (136997467).

684987305 is a wasteful number, since it uses less digits than its factorization.

684987305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136997466.

The product of its (nonzero) digits is 1451520, while the sum is 50.

The square root of 684987305 is about 26172.2621299726. The cubic root of 684987305 is about 881.5105362488.

The spelling of 684987305 in words is "six hundred eighty-four million, nine hundred eighty-seven thousand, three hundred five".