684945871 has 4 divisors (see below), whose sum is σ = 697869432. Its totient is φ = 672022312.

The previous prime is 684945853. The next prime is 684945883. The reversal of 684945871 is 178549486.

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

It is a cyclic number.

It is not a de Polignac number, because 684945871 - 2¹¹ = 684943823 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (684945851) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6461701 + ... + 6461806.

It is an arithmetic number, because the mean of its divisors is an integer number (174467358).

Almost surely, 2^684945871 is an apocalyptic number.

684945871 is a deficient number, since it is larger than the sum of its proper divisors (12923561).

684945871 is a wasteful number, since it uses less digits than its factorization.

684945871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12923560.

The product of its digits is 1935360, while the sum is 52.

The square root of 684945871 is about 26171.4705547854. The cubic root of 684945871 is about 881.4927620780.

The spelling of 684945871 in words is "six hundred eighty-four million, nine hundred forty-five thousand, eight hundred seventy-one".