521099881 has 4 divisors (see below), whose sum is σ = 529642564. Its totient is φ = 512557200.

The previous prime is 521099867. The next prime is 521099893. The reversal of 521099881 is 188990125.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 101505625 + 419594256 = 10075^2 + 20484^2 .

It is a cyclic number.

It is not a de Polignac number, because 521099881 - 2⁵ = 521099849 is a prime.

It is a super-2 number, since 2×521099881² = 543090171956428322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (521099981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4271250 + ... + 4271371.

It is an arithmetic number, because the mean of its divisors is an integer number (132410641).

Almost surely, 2^521099881 is an apocalyptic number.

It is an amenable number.

521099881 is a deficient number, since it is larger than the sum of its proper divisors (8542683).

521099881 is an equidigital number, since it uses as much as digits as its factorization.

521099881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8542682.

The product of its (nonzero) digits is 51840, while the sum is 43.

The square root of 521099881 is about 22827.6122492038. The cubic root of 521099881 is about 804.7117165334.

The spelling of 521099881 in words is "five hundred twenty-one million, ninety-nine thousand, eight hundred eighty-one".