817720120 has 64 divisors (see below), whose sum is σ = 2118156480. Its totient is φ = 278301696.

The previous prime is 817720109. The next prime is 817720129. The reversal of 817720120 is 21027718.

817720120 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (817720129) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27702 + ... + 49018.

It is an arithmetic number, because the mean of its divisors is an integer number (33096195).

Almost surely, 2^817720120 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 817720120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1059078240).

817720120 is an abundant number, since it is smaller than the sum of its proper divisors (1300436360).

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

817720120 is a wasteful number, since it uses less digits than its factorization.

817720120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21472 (or 21468 counting only the distinct ones).

The product of its (nonzero) digits is 1568, while the sum is 28.

The square root of 817720120 is about 28595.8059861932. The cubic root of 817720120 is about 935.1218997082.

Adding to 817720120 its reverse (21027718), we get a palindrome (838747838).

The spelling of 817720120 in words is "eight hundred seventeen million, seven hundred twenty thousand, one hundred twenty".