1684888561 has 2 divisors, whose sum is σ = 1684888562. Its totient is φ = 1684888560.

The previous prime is 1684888519. The next prime is 1684888607. The reversal of 1684888561 is 1658884861.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1683542961 + 1345600 = 41031^2 + 1160^2 .

It is a cyclic number.

It is not a de Polignac number, because 1684888561 - 2²⁵ = 1651334129 is a prime.

It is not a weakly prime, because it can be changed into another prime (1684888501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 842444280 + 842444281.

It is an arithmetic number, because the mean of its divisors is an integer number (842444281).

Almost surely, 2^1684888561 is an apocalyptic number.

It is an amenable number.

1684888561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1684888561 is an equidigital number, since it uses as much as digits as its factorization.

1684888561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2949120, while the sum is 55.

The square root of 1684888561 is about 41047.3940829378. The cubic root of 1684888561 is about 1189.9363384252.

The spelling of 1684888561 in words is "one billion, six hundred eighty-four million, eight hundred eighty-eight thousand, five hundred sixty-one".