1849999861609 has 9 divisors (see below), whose sum is σ = 1876521143191. Its totient is φ = 1823848315240.

The previous prime is 1849999861571. The next prime is 1849999861643. The reversal of 1849999861609 is 9061689999481.

It is a happy number.

The square root of 1849999861609 is 1360147.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 55396683225 + 1794603178384 = 235365^2 + 1339628^2 .

It is not a de Polignac number, because 1849999861609 - 2¹³ = 1849999853417 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1849999861009) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 96560859 + ... + 96580015.

Almost surely, 2^{1849999861609} is an apocalyptic number.

1849999861609 is the 1360147-th square number.

1849999861609 is the 680074-th centered octagonal number.

It is an amenable number.

1849999861609 is a deficient number, since it is larger than the sum of its proper divisors (26521281582).

1849999861609 is an frugal number, since it uses more digits than its factorization.

1849999861609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38456 (or 19228 counting only the distinct ones).

The product of its (nonzero) digits is 544195584, while the sum is 79.

The spelling of 1849999861609 in words is "one trillion, eight hundred forty-nine billion, nine hundred ninety-nine million, eight hundred sixty-one thousand, six hundred nine".