817315920 has 120 divisors (see below), whose sum is σ = 2846546976. Its totient is φ = 217945728.

The previous prime is 817315883. The next prime is 817315927. The reversal of 817315920 is 29513718.

It is a tau number, because it is divible by the number of its divisors (120).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (817315927) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 1582 + ... + 40461.

Almost surely, 2^817315920 is an apocalyptic number.

817315920 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 817315920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1423273488).

817315920 is an abundant number, since it is smaller than the sum of its proper divisors (2029231056).

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

817315920 is a wasteful number, since it uses less digits than its factorization.

817315920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42071 (or 42053 counting only the distinct ones).

The product of its (nonzero) digits is 15120, while the sum is 36.

The square root of 817315920 is about 28588.7376426452. The cubic root of 817315920 is about 934.9677970359.

The spelling of 817315920 in words is "eight hundred seventeen million, three hundred fifteen thousand, nine hundred twenty".