1809440640 has 384 divisors, whose sum is σ = 7458199200. Its totient is φ = 413392896.

The previous prime is 1809440629. The next prime is 1809440641. The reversal of 1809440640 is 460449081.

It is a happy number.

1809440640 is a `hidden beast` number, since 1 + 8 + 0 + 9 + 4 + 4 + 0 + 640 = 666.

It is a tau number, because it is divible by the number of its divisors (384).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 1809440595 and 1809440604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1809440641) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 845652 + ... + 847788.

Almost surely, 2^1809440640 is an apocalyptic number.

1809440640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1809440640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3729099600).

1809440640 is an abundant number, since it is smaller than the sum of its proper divisors (5648758560).

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

1809440640 is a wasteful number, since it uses less digits than its factorization.

1809440640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2179 (or 2154 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 36.

The square root of 1809440640 is about 42537.5203790724. The cubic root of 1809440640 is about 1218.5633541394.

The spelling of 1809440640 in words is "one billion, eight hundred nine million, four hundred forty thousand, six hundred forty".