521681057 has 4 divisors (see below), whose sum is σ = 552368196. Its totient is φ = 490993920.

The previous prime is 521681053. The next prime is 521681077. The reversal of 521681057 is 750186125.

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 366952336 + 154728721 = 19156^2 + 12439^2 .

It is a cyclic number.

It is not a de Polignac number, because 521681057 - 2² = 521681053 is a prime.

It is a super-2 number, since 2×521681057² = 544302250465274498, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (521681053) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15343544 + ... + 15343577.

It is an arithmetic number, because the mean of its divisors is an integer number (138092049).

Almost surely, 2^521681057 is an apocalyptic number.

It is an amenable number.

521681057 is a deficient number, since it is larger than the sum of its proper divisors (30687139).

521681057 is a wasteful number, since it uses less digits than its factorization.

521681057 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30687138.

The product of its (nonzero) digits is 16800, while the sum is 35.

The square root of 521681057 is about 22840.3383731503. The cubic root of 521681057 is about 805.0107669303.

The spelling of 521681057 in words is "five hundred twenty-one million, six hundred eighty-one thousand, fifty-seven".