1684741921 has 4 divisors (see below), whose sum is σ = 1742836500. Its totient is φ = 1626647344.

The previous prime is 1684741907. The next prime is 1684741943. The reversal of 1684741921 is 1291474861.

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 285981921 + 1398760000 = 16911^2 + 37400^2 .

It is a cyclic number.

It is not a de Polignac number, because 1684741921 - 2¹⁷ = 1684610849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1684748921) 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, 29047246 + ... + 29047303.

It is an arithmetic number, because the mean of its divisors is an integer number (435709125).

Almost surely, 2^1684741921 is an apocalyptic number.

It is an amenable number.

1684741921 is a deficient number, since it is larger than the sum of its proper divisors (58094579).

1684741921 is an equidigital number, since it uses as much as digits as its factorization.

1684741921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58094578.

The product of its digits is 96768, while the sum is 43.

The square root of 1684741921 is about 41045.6078161842. The cubic root of 1684741921 is about 1189.9018163939.

The spelling of 1684741921 in words is "one billion, six hundred eighty-four million, seven hundred forty-one thousand, nine hundred twenty-one".