66590521 has 4 divisors (see below), whose sum is σ = 66660352. Its totient is φ = 66520692.

The previous prime is 66590507. The next prime is 66590569. The reversal of 66590521 is 12509566.

It is a happy number.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12509566 = 2 ⋅6254783.

It is a cyclic number.

It is not a de Polignac number, because 66590521 - 2⁹ = 66590009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66590501) 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, 33465 + ... + 35398.

It is an arithmetic number, because the mean of its divisors is an integer number (16665088).

Almost surely, 2^66590521 is an apocalyptic number.

It is an amenable number.

66590521 is a deficient number, since it is larger than the sum of its proper divisors (69831).

66590521 is an equidigital number, since it uses as much as digits as its factorization.

66590521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69830.

The product of its (nonzero) digits is 16200, while the sum is 34.

The square root of 66590521 is about 8160.3015262918. The cubic root of 66590521 is about 405.3256964497.

The spelling of 66590521 in words is "sixty-six million, five hundred ninety thousand, five hundred twenty-one".