817920 has 108 divisors (see below), whose sum is σ = 2869776. Its totient is φ = 215040.

The previous prime is 817919. The next prime is 817933. The reversal of 817920 is 29718.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 11485 + ... + 11555.

It is an arithmetic number, because the mean of its divisors is an integer number (26572).

2⁸¹⁷⁹²⁰ is an apocalyptic number.

817920 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 817920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1434888).

817920 is an abundant number, since it is smaller than the sum of its proper divisors (2051856).

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

817920 is a wasteful number, since it uses less digits than its factorization.

817920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98 (or 81 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 27.

The square root of 817920 is about 904.3892967080. The cubic root of 817920 is about 93.5198085897.

It can be divided in two parts, 81 and 7920, that added together give a triangular number (8001 = T₁₂₆).

The spelling of 817920 in words is "eight hundred seventeen thousand, nine hundred twenty".