1684220409 has 18 divisors (see below), whose sum is σ = 2458224990. Its totient is φ = 1111182336.

The previous prime is 1684220407. The next prime is 1684220411. The reversal of 1684220409 is 9040224861.

It is an interprime number because it is at equal distance from previous prime (1684220407) and next prime (1684220411).

It can be written as a sum of positive squares in 3 ways, for example, as 558282384 + 1125938025 = 23628^2 + 33555^2 .

It is not a de Polignac number, because 1684220409 - 2¹ = 1684220407 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1684220407) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 74737 + ... + 94625.

It is an arithmetic number, because the mean of its divisors is an integer number (136568055).

Almost surely, 2^1684220409 is an apocalyptic number.

It is an amenable number.

1684220409 is a deficient number, since it is larger than the sum of its proper divisors (774004581).

1684220409 is an equidigital number, since it uses as much as digits as its factorization.

1684220409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20089 (or 19989 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 36.

The square root of 1684220409 is about 41039.2544888428. The cubic root of 1684220409 is about 1189.7790256547.

The spelling of 1684220409 in words is "one billion, six hundred eighty-four million, two hundred twenty thousand, four hundred nine".