18552561 has 4 divisors (see below), whose sum is σ = 24736752. Its totient is φ = 12368372.

The previous prime is 18552557. The next prime is 18552581. The reversal of 18552561 is 16525581.

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 a cyclic number.

It is not a de Polignac number, because 18552561 - 2² = 18552557 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18552551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3092091 + ... + 3092096.

It is an arithmetic number, because the mean of its divisors is an integer number (6184188).

Almost surely, 2^18552561 is an apocalyptic number.

It is an amenable number.

18552561 is a deficient number, since it is larger than the sum of its proper divisors (6184191).

18552561 is an equidigital number, since it uses as much as digits as its factorization.

18552561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6184190.

The product of its digits is 12000, while the sum is 33.

The square root of 18552561 is about 4307.2683919162. The cubic root of 18552561 is about 264.7288599691.

The spelling of 18552561 in words is "eighteen million, five hundred fifty-two thousand, five hundred sixty-one".