18107521 has 2 divisors, whose sum is σ = 18107522. Its totient is φ = 18107520.

The previous prime is 18107491. The next prime is 18107539. The reversal of 18107521 is 12570181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10817521 + 7290000 = 3289^2 + 2700^2 .

It is a cyclic number.

It is not a de Polignac number, because 18107521 - 2⁵ = 18107489 is a prime.

It is not a weakly prime, because it can be changed into another prime (18107581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9053760 + 9053761.

It is an arithmetic number, because the mean of its divisors is an integer number (9053761).

Almost surely, 2^18107521 is an apocalyptic number.

It is an amenable number.

18107521 is a deficient number, since it is larger than the sum of its proper divisors (1).

18107521 is an equidigital number, since it uses as much as digits as its factorization.

18107521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 560, while the sum is 25.

The square root of 18107521 is about 4255.2932918895. The cubic root of 18107521 is about 262.5949274210.

The spelling of 18107521 in words is "eighteen million, one hundred seven thousand, five hundred twenty-one".