18526721 has 2 divisors, whose sum is σ = 18526722. Its totient is φ = 18526720.

The previous prime is 18526693. The next prime is 18526723. The reversal of 18526721 is 12762581.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15840400 + 2686321 = 3980^2 + 1639^2 .

It is a cyclic number.

It is not a de Polignac number, because 18526721 - 2¹⁴ = 18510337 is a prime.

Together with 18526723, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18526723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9263360 + 9263361.

It is an arithmetic number, because the mean of its divisors is an integer number (9263361).

Almost surely, 2^18526721 is an apocalyptic number.

It is an amenable number.

18526721 is a deficient number, since it is larger than the sum of its proper divisors (1).

18526721 is an equidigital number, since it uses as much as digits as its factorization.

18526721 is an odious number, because the sum of its binary digits is odd.

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

The square root of 18526721 is about 4304.2677658343. The cubic root of 18526721 is about 264.6058981120.

The spelling of 18526721 in words is "eighteen million, five hundred twenty-six thousand, seven hundred twenty-one".