663575521 has 4 divisors (see below), whose sum is σ = 758372032. Its totient is φ = 568779012.

The previous prime is 663575509. The next prime is 663575533. The reversal of 663575521 is 125575366.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (663575509) and next prime (663575533).

It is a cyclic number.

It is not a de Polignac number, because 663575521 - 2⁹ = 663575009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (663575021) 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, 47398245 + ... + 47398258.

It is an arithmetic number, because the mean of its divisors is an integer number (189593008).

Almost surely, 2^663575521 is an apocalyptic number.

It is an amenable number.

663575521 is a deficient number, since it is larger than the sum of its proper divisors (94796511).

663575521 is an equidigital number, since it uses as much as digits as its factorization.

663575521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94796510.

The product of its digits is 189000, while the sum is 40.

The square root of 663575521 is about 25759.9596467075. The cubic root of 663575521 is about 872.2281903051.

It can be divided in two parts, 6635755 and 21, that added together give a square (6635776 = 2576²).

The spelling of 663575521 in words is "six hundred sixty-three million, five hundred seventy-five thousand, five hundred twenty-one".