521532661 has 8 divisors (see below), whose sum is σ = 561849624. Its totient is φ = 481244160.

The previous prime is 521532643. The next prime is 521532679. The reversal of 521532661 is 166235125.

It is an interprime number because it is at equal distance from previous prime (521532643) and next prime (521532679).

It can be written as a sum of positive squares in 4 ways, for example, as 323761 + 521208900 = 569^2 + 22830^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 521532661 - 2¹⁵ = 521499893 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521532611) 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 7 ways as a sum of consecutive naturals, for example, 45285 + ... + 55621.

It is an arithmetic number, because the mean of its divisors is an integer number (70231203).

Almost surely, 2^521532661 is an apocalyptic number.

It is an amenable number.

521532661 is a deficient number, since it is larger than the sum of its proper divisors (40316963).

521532661 is a wasteful number, since it uses less digits than its factorization.

521532661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14231.

The product of its digits is 10800, while the sum is 31.

The square root of 521532661 is about 22837.0895912767. The cubic root of 521532661 is about 804.9344292874.

Adding to 521532661 its reverse (166235125), we get a palindrome (687767786).

The spelling of 521532661 in words is "five hundred twenty-one million, five hundred thirty-two thousand, six hundred sixty-one".