521891812 has 12 divisors (see below), whose sum is σ = 983565436. Its totient is φ = 240873120.

The previous prime is 521891803. The next prime is 521891813. The reversal of 521891812 is 218198125.

It can be written as a sum of positive squares in 2 ways, for example, as 164454976 + 357436836 = 12824^2 + 18906^2 .

It is not an unprimeable number, because it can be changed into a prime (521891813) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5018139 + ... + 5018242.

Almost surely, 2^521891812 is an apocalyptic number.

521891812 is a gapful number since it is divisible by the number (52) formed by its first and last digit.

It is an amenable number.

521891812 is a deficient number, since it is larger than the sum of its proper divisors (461673624).

521891812 is a wasteful number, since it uses less digits than its factorization.

521891812 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10036398 (or 10036396 counting only the distinct ones).

The product of its digits is 11520, while the sum is 37.

The square root of 521891812 is about 22844.9515648425. The cubic root of 521891812 is about 805.1191583187.

The spelling of 521891812 in words is "five hundred twenty-one million, eight hundred ninety-one thousand, eight hundred twelve".