1684781057 has 4 divisors (see below), whose sum is σ = 1689025236. Its totient is φ = 1680536880.

The previous prime is 1684781047. The next prime is 1684781083. The reversal of 1684781057 is 7501874861.

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 436642816 + 1248138241 = 20896^2 + 35329^2 .

It is a cyclic number.

It is not a de Polignac number, because 1684781057 - 2⁴ = 1684781041 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1684781017) by changing a digit.

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, 2121494 + ... + 2122287.

It is an arithmetic number, because the mean of its divisors is an integer number (422256309).

Almost surely, 2^1684781057 is an apocalyptic number.

It is an amenable number.

1684781057 is a deficient number, since it is larger than the sum of its proper divisors (4244179).

1684781057 is an equidigital number, since it uses as much as digits as its factorization.

1684781057 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4244178.

The product of its (nonzero) digits is 376320, while the sum is 47.

The square root of 1684781057 is about 41046.0845513917. The cubic root of 1684781057 is about 1189.9110299983.

The spelling of 1684781057 in words is "one billion, six hundred eighty-four million, seven hundred eighty-one thousand, fifty-seven".