1809689871972 has 48 divisors (see below), whose sum is σ = 4302632017152. Its totient is φ = 591800052480.

The previous prime is 1809689871971. The next prime is 1809689872013. The reversal of 1809689871972 is 2791789869081.

It is a junction number, because it is equal to n+sod(n) for n = 1809689871894 and 1809689871903.

It is not an unprimeable number, because it can be changed into a prime (1809689871971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8163072 + ... + 8381832.

It is an arithmetic number, because the mean of its divisors is an integer number (89638167024).

Almost surely, 2^{1809689871972} is an apocalyptic number.

1809689871972 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1809689871972 is an abundant number, since it is smaller than the sum of its proper divisors (2492942145180).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1809689871972 is a wasteful number, since it uses less digits than its factorization.

1809689871972 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 231828 (or 231826 counting only the distinct ones).

The product of its (nonzero) digits is 219469824, while the sum is 75.

The spelling of 1809689871972 in words is "one trillion, eight hundred nine billion, six hundred eighty-nine million, eight hundred seventy-one thousand, nine hundred seventy-two".