1809167572809 has 9 divisors (see below), whose sum is σ = 2613247878189. Its totient is φ = 1206109025100.

The previous prime is 1809167572783. The next prime is 1809167572813. The reversal of 1809167572809 is 9082757619081.

The square root of 1809167572809 is 1345053.

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

It is a tau number, because it is divible by the number of its divisors (9).

It is a de Polignac number, because none of the positive numbers 2^k-1809167572809 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1809167572889) 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, 3810984 + ... + 4259334.

Almost surely, 2^{1809167572809} is an apocalyptic number.

1809167572809 is the 1345053-rd square number.

1809167572809 is the 672527-th centered octagonal number.

It is an amenable number.

1809167572809 is a deficient number, since it is larger than the sum of its proper divisors (804080305380).

1809167572809 is an frugal number, since it uses more digits than its factorization.

1809167572809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 896708 (or 448354 counting only the distinct ones).

The product of its (nonzero) digits is 15240960, while the sum is 63.

The spelling of 1809167572809 in words is "one trillion, eight hundred nine billion, one hundred sixty-seven million, five hundred seventy-two thousand, eight hundred nine".