1684678357 has 4 divisors (see below), whose sum is σ = 1684762380. Its totient is φ = 1684594336.

The previous prime is 1684678343. The next prime is 1684678361. The reversal of 1684678357 is 7538764861.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 7538764861 = 29 ⋅259957409.

It can be written as a sum of positive squares in 2 ways, for example, as 831687921 + 852990436 = 28839^2 + 29206^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1684678357 is a prime.

It is a super-3 number, since 3×1684678357³ (a number of 29 digits) contains 333 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1684678298 and 1684678307.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1684678327) 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, 7569 + ... + 58537.

It is an arithmetic number, because the mean of its divisors is an integer number (421190595).

Almost surely, 2^1684678357 is an apocalyptic number.

It is an amenable number.

1684678357 is a deficient number, since it is larger than the sum of its proper divisors (84023).

1684678357 is an equidigital number, since it uses as much as digits as its factorization.

1684678357 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84022.

The product of its digits is 6773760, while the sum is 55.

The square root of 1684678357 is about 41044.8334994796. The cubic root of 1684678357 is about 1189.8868515162.

The spelling of 1684678357 in words is "one billion, six hundred eighty-four million, six hundred seventy-eight thousand, three hundred fifty-seven".