816257520 has 320 divisors, whose sum is σ = 3106051200. Its totient is φ = 195747840.

The previous prime is 816257513. The next prime is 816257521. The reversal of 816257520 is 25752618.

It is a happy number.

816257520 is a `hidden beast` number, since 8 + 1 + 62 + 575 + 20 = 666.

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 (816257521) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1150926 + ... + 1151634.

It is an arithmetic number, because the mean of its divisors is an integer number (9706410).

Almost surely, 2^816257520 is an apocalyptic number.

816257520 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 816257520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1553025600).

816257520 is an abundant number, since it is smaller than the sum of its proper divisors (2289793680).

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

816257520 is a wasteful number, since it uses less digits than its factorization.

816257520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 785 (or 773 counting only the distinct ones).

The product of its (nonzero) digits is 33600, while the sum is 36.

The square root of 816257520 is about 28570.2208601894. The cubic root of 816257520 is about 934.5640374637.

The spelling of 816257520 in words is "eight hundred sixteen million, two hundred fifty-seven thousand, five hundred twenty".