18672521 has 4 divisors (see below), whose sum is σ = 21340032. Its totient is φ = 16005012.

The previous prime is 18672517. The next prime is 18672541. The reversal of 18672521 is 12527681.

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 18672521 - 2² = 18672517 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18672541) 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, 1333745 + ... + 1333758.

It is an arithmetic number, because the mean of its divisors is an integer number (5335008).

Almost surely, 2^18672521 is an apocalyptic number.

It is an amenable number.

18672521 is a deficient number, since it is larger than the sum of its proper divisors (2667511).

18672521 is an equidigital number, since it uses as much as digits as its factorization.

18672521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2667510.

The product of its digits is 6720, while the sum is 32.

The square root of 18672521 is about 4321.1712532599. The cubic root of 18672521 is about 265.2982094460.

The spelling of 18672521 in words is "eighteen million, six hundred seventy-two thousand, five hundred twenty-one".