1818521 has 2 divisors, whose sum is σ = 1818522. Its totient is φ = 1818520.

The previous prime is 1818499. The next prime is 1818527. The reversal of 1818521 is 1258181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1792921 + 25600 = 1339^2 + 160^2 .

It is an emirp because it is prime and its reverse (1258181) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1818521 - 2⁶ = 1818457 is a prime.

It is a Sophie Germain prime.

It is an alternating number because its digits alternate between odd and even.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1818527) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 909260 + 909261.

It is an arithmetic number, because the mean of its divisors is an integer number (909261).

2^1818521 is an apocalyptic number.

It is an amenable number.

1818521 is a deficient number, since it is larger than the sum of its proper divisors (1).

1818521 is an equidigital number, since it uses as much as digits as its factorization.

1818521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 640, while the sum is 26.

The square root of 1818521 is about 1348.5254910457. The cubic root of 1818521 is about 122.0598335905.

The spelling of 1818521 in words is "one million, eight hundred eighteen thousand, five hundred twenty-one".