818705521 has 4 divisors (see below), whose sum is σ = 818821872. Its totient is φ = 818589172.

The previous prime is 818705501. The next prime is 818705527. The reversal of 818705521 is 125507818.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 818705521 - 2¹⁵ = 818672753 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (818705527) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 46891 + ... + 61936.

It is an arithmetic number, because the mean of its divisors is an integer number (204705468).

Almost surely, 2^818705521 is an apocalyptic number.

It is an amenable number.

818705521 is a deficient number, since it is larger than the sum of its proper divisors (116351).

818705521 is a wasteful number, since it uses less digits than its factorization.

818705521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 116350.

The product of its (nonzero) digits is 22400, while the sum is 37.

The square root of 818705521 is about 28613.0306154381. The cubic root of 818705521 is about 935.4973746163.

The spelling of 818705521 in words is "eight hundred eighteen million, seven hundred five thousand, five hundred twenty-one".