521564437 has 4 divisors (see below), whose sum is σ = 552244716. Its totient is φ = 490884160.

The previous prime is 521564431. The next prime is 521564569. The reversal of 521564437 is 734465125.

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 466819236 + 54745201 = 21606^2 + 7399^2 .

It is a cyclic number.

It is not a de Polignac number, because 521564437 - 2¹¹ = 521562389 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 521564396 and 521564405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521564431) 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, 15340114 + ... + 15340147.

It is an arithmetic number, because the mean of its divisors is an integer number (138061179).

Almost surely, 2^521564437 is an apocalyptic number.

It is an amenable number.

521564437 is a deficient number, since it is larger than the sum of its proper divisors (30680279).

521564437 is a wasteful number, since it uses less digits than its factorization.

521564437 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30680278.

The product of its digits is 100800, while the sum is 37.

The square root of 521564437 is about 22837.7852910478. The cubic root of 521564437 is about 804.9507766669.

The spelling of 521564437 in words is "five hundred twenty-one million, five hundred sixty-four thousand, four hundred thirty-seven".