18240251 has 2 divisors, whose sum is σ = 18240252. Its totient is φ = 18240250.

The previous prime is 18240239. The next prime is 18240253. The reversal of 18240251 is 15204281.

It is a strong prime.

It is an emirp because it is prime and its reverse (15204281) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18240251 - 2¹⁰ = 18239227 is a prime.

Together with 18240253, 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 (18240253) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9120125 + 9120126.

It is an arithmetic number, because the mean of its divisors is an integer number (9120126).

Almost surely, 2^18240251 is an apocalyptic number.

18240251 is a deficient number, since it is larger than the sum of its proper divisors (1).

18240251 is an equidigital number, since it uses as much as digits as its factorization.

18240251 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 640, while the sum is 23.

The square root of 18240251 is about 4270.8606860913. The cubic root of 18240251 is about 263.2349820544.

The spelling of 18240251 in words is "eighteen million, two hundred forty thousand, two hundred fifty-one".