684704651 has 4 divisors (see below), whose sum is σ = 684929400. Its totient is φ = 684479904.

The previous prime is 684704639. The next prime is 684704681. The reversal of 684704651 is 156407486.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 156407486 = 2 ⋅78203743.

It is a cyclic number.

It is not a de Polignac number, because 684704651 - 2¹⁴ = 684688267 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 684704599 and 684704608.

It is not an unprimeable number, because it can be changed into a prime (684704611) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 107741 + ... + 113918.

It is an arithmetic number, because the mean of its divisors is an integer number (171232350).

Almost surely, 2^684704651 is an apocalyptic number.

684704651 is a deficient number, since it is larger than the sum of its proper divisors (224749).

684704651 is a wasteful number, since it uses less digits than its factorization.

684704651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 224748.

The product of its (nonzero) digits is 161280, while the sum is 41.

The square root of 684704651 is about 26166.8616956638. The cubic root of 684704651 is about 881.3892703719.

The spelling of 684704651 in words is "six hundred eighty-four million, seven hundred four thousand, six hundred fifty-one".