18530521 has 4 divisors (see below), whose sum is σ = 18541312. Its totient is φ = 18519732.

The previous prime is 18530461. The next prime is 18530537. The reversal of 18530521 is 12503581.

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 a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 12503581 = 401 ⋅31181.

It is a cyclic number.

It is not a de Polignac number, because 18530521 - 2²¹ = 16433369 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18530021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2181 + ... + 6466.

It is an arithmetic number, because the mean of its divisors is an integer number (4635328).

Almost surely, 2^18530521 is an apocalyptic number.

It is an amenable number.

18530521 is a deficient number, since it is larger than the sum of its proper divisors (10791).

18530521 is an equidigital number, since it uses as much as digits as its factorization.

18530521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10790.

The product of its (nonzero) digits is 1200, while the sum is 25.

The square root of 18530521 is about 4304.7091655535. The cubic root of 18530521 is about 264.6239879056.

The spelling of 18530521 in words is "eighteen million, five hundred thirty thousand, five hundred twenty-one".