18078257 has 2 divisors, whose sum is σ = 18078258. Its totient is φ = 18078256.

The previous prime is 18078217. The next prime is 18078287. The reversal of 18078257 is 75287081.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17774656 + 303601 = 4216^2 + 551^2 .

It is an emirp because it is prime and its reverse (75287081) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18078257 - 2¹⁰ = 18077233 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18078257.

It is not a weakly prime, because it can be changed into another prime (18078217) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9039128 + 9039129.

It is an arithmetic number, because the mean of its divisors is an integer number (9039129).

Almost surely, 2^18078257 is an apocalyptic number.

It is an amenable number.

18078257 is a deficient number, since it is larger than the sum of its proper divisors (1).

18078257 is an equidigital number, since it uses as much as digits as its factorization.

18078257 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 31360, while the sum is 38.

The square root of 18078257 is about 4251.8533605946. The cubic root of 18078257 is about 262.4533891541.

The spelling of 18078257 in words is "eighteen million, seventy-eight thousand, two hundred fifty-seven".