809857440 has 480 divisors, whose sum is σ = 3337044480. Its totient is φ = 181149696.

The previous prime is 809857429. The next prime is 809857459. The reversal of 809857440 is 44758908.

It is a tau number, because it is divible by the number of its divisors (480).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 7166824 + ... + 7166936.

It is an arithmetic number, because the mean of its divisors is an integer number (6952176).

Almost surely, 2^809857440 is an apocalyptic number.

809857440 is a gapful number since it is divisible by the number (80) 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 809857440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1668522240).

809857440 is an abundant number, since it is smaller than the sum of its proper divisors (2527187040).

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

809857440 is a wasteful number, since it uses less digits than its factorization.

809857440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 226 (or 209 counting only the distinct ones).

The product of its (nonzero) digits is 322560, while the sum is 45.

The square root of 809857440 is about 28457.9943073998. The cubic root of 809857440 is about 932.1150612854.

The spelling of 809857440 in words is "eight hundred nine million, eight hundred fifty-seven thousand, four hundred forty".