1809777816 has 640 divisors, whose sum is σ = 7025356800. Its totient is φ = 420837120.

The previous prime is 1809777811. The next prime is 1809777833. The reversal of 1809777816 is 6187779081.

1809777816 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1809777811) by changing a digit.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 21804511 + ... + 21804593.

It is an arithmetic number, because the mean of its divisors is an integer number (10977120).

Almost surely, 2^1809777816 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1809777816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3512678400).

1809777816 is an abundant number, since it is smaller than the sum of its proper divisors (5215578984).

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

1809777816 is a wasteful number, since it uses less digits than its factorization.

1809777816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 161 (or 148 counting only the distinct ones).

The product of its (nonzero) digits is 1185408, while the sum is 54.

The square root of 1809777816 is about 42541.4834720182. The cubic root of 1809777816 is about 1218.6390395548.

The spelling of 1809777816 in words is "one billion, eight hundred nine million, seven hundred seventy-seven thousand, eight hundred sixteen".