1808921388 has 48 divisors (see below), whose sum is σ = 4433990400. Its totient is φ = 572873664.

The previous prime is 1808921333. The next prime is 1808921399. The reversal of 1808921388 is 8831298081.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19131 + ... + 63117.

It is an arithmetic number, because the mean of its divisors is an integer number (92374800).

Almost surely, 2^1808921388 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 1808921388, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2216995200).

1808921388 is an abundant number, since it is smaller than the sum of its proper divisors (2625069012).

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

1808921388 is a wasteful number, since it uses less digits than its factorization.

1808921388 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44166 (or 44164 counting only the distinct ones).

The product of its (nonzero) digits is 221184, while the sum is 48.

The square root of 1808921388 is about 42531.4164824074. The cubic root of 1808921388 is about 1218.4467799931.

The spelling of 1808921388 in words is "one billion, eight hundred eight million, nine hundred twenty-one thousand, three hundred eighty-eight".