521561601 has 12 divisors (see below), whose sum is σ = 821854800. Its totient is φ = 316097880.

The previous prime is 521561597. The next prime is 521561641. The reversal of 521561601 is 106165125.

It is a happy number.

521561601 is a `hidden beast` number, since 5 + 2 + 1 + 56 + 1 + 601 = 666.

It is not a de Polignac number, because 521561601 - 2² = 521561597 is a prime.

It is not an unprimeable number, because it can be changed into a prime (521561641) 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 11 ways as a sum of consecutive naturals, for example, 2634051 + ... + 2634248.

It is an arithmetic number, because the mean of its divisors is an integer number (68487900).

Almost surely, 2^521561601 is an apocalyptic number.

It is an amenable number.

521561601 is a deficient number, since it is larger than the sum of its proper divisors (300293199).

521561601 is a wasteful number, since it uses less digits than its factorization.

521561601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5268316 (or 5268313 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 27.

The square root of 521561601 is about 22837.7232008797. The cubic root of 521561601 is about 804.9493176944.

The spelling of 521561601 in words is "five hundred twenty-one million, five hundred sixty-one thousand, six hundred one".