1816987809 has 16 divisors (see below), whose sum is σ = 2981724032. Its totient is φ = 958411008.

The previous prime is 1816987769. The next prime is 1816987811. The reversal of 1816987809 is 9087896181.

It is not a de Polignac number, because 1816987809 - 2¹¹ = 1816985761 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1816987709) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3327544 + ... + 3328089.

It is an arithmetic number, because the mean of its divisors is an integer number (186357752).

Almost surely, 2^1816987809 is an apocalyptic number.

It is an amenable number.

1816987809 is a deficient number, since it is larger than the sum of its proper divisors (1164736223).

1816987809 is a wasteful number, since it uses less digits than its factorization.

1816987809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6655656.

The product of its (nonzero) digits is 1741824, while the sum is 57.

The square root of 1816987809 is about 42626.1399730259. The cubic root of 1816987809 is about 1220.2552115464.

The spelling of 1816987809 in words is "one billion, eight hundred sixteen million, nine hundred eighty-seven thousand, eight hundred nine".