817745840 has 40 divisors (see below), whose sum is σ = 1919737248. Its totient is φ = 323919360.

The previous prime is 817745839. The next prime is 817745879. The reversal of 817745840 is 48547718.

It is a tau number, because it is divible by the number of its divisors (40).

It is a junction number, because it is equal to n+sod(n) for n = 817745791 and 817745800.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 41381 + ... + 57860.

Almost surely, 2^817745840 is an apocalyptic number.

817745840 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

817745840 is an abundant number, since it is smaller than the sum of its proper divisors (1101991408).

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

817745840 is a wasteful number, since it uses less digits than its factorization.

817745840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99357 (or 99351 counting only the distinct ones).

The product of its (nonzero) digits is 250880, while the sum is 44.

The square root of 817745840 is about 28596.2556989547. The cubic root of 817745840 is about 935.1317038300.

The spelling of 817745840 in words is "eight hundred seventeen million, seven hundred forty-five thousand, eight hundred forty".