817211520 has 192 divisors, whose sum is σ = 2837030040. Its totient is φ = 216760320.

The previous prime is 817211501. The next prime is 817211531. The reversal of 817211520 is 25112718.

It can be written as a sum of positive squares in 4 ways, for example, as 283046976 + 534164544 = 16824^2 + 23112^2 .

It is a tau number, because it is divible by the number of its divisors (192).

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 23 ways as a sum of consecutive naturals, for example, 1940910 + ... + 1941330.

Almost surely, 2^817211520 is an apocalyptic number.

817211520 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 817211520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1418515020).

817211520 is an abundant number, since it is smaller than the sum of its proper divisors (2019818520).

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

817211520 is a wasteful number, since it uses less digits than its factorization.

817211520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 783 (or 768 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 27.

The square root of 817211520 is about 28586.9116904922. The cubic root of 817211520 is about 934.9279859127.

The spelling of 817211520 in words is "eight hundred seventeen million, two hundred eleven thousand, five hundred twenty".